ABSTRACT Embedding submicrocavities is an effective approach to improve the light out-coupling efficiency(LOCE)for planar perovskite light-emitting diodes(PeLEDs).In this work,we employ phenethylammonium iodide(PEAI)t...ABSTRACT Embedding submicrocavities is an effective approach to improve the light out-coupling efficiency(LOCE)for planar perovskite light-emitting diodes(PeLEDs).In this work,we employ phenethylammonium iodide(PEAI)to trigger the Ostwald ripening for the downward recrystallization of perovskite,resulting in spontaneous formation of buried submicrocavities as light output coupler.The simulation suggests the buried submicrocavities can improve the LOCE from 26.8 to 36.2%for near-infrared light.Therefore,PeLED yields peak external quantum efficiency(EQE)increasing from 17.3%at current density of 114 mA cm^(−2)to 25.5%at current density of 109 mA cm^(−2)and a radiance increasing from 109 to 487 W sr^(−1)m^(−2)with low rolling-off.The turn-on voltage decreased from 1.25 to 1.15 V at 0.1 W sr^(−1)m^(−2).Besides,downward recrystallization process slightly reduces the trap density from 8.90×10^(15)to 7.27×10^(15)cm^(−3).This work provides a self-assembly method to integrate buried output coupler for boosting the performance of PeLEDs.展开更多
采用热重分析法测定了在氮气气氛中5℃/min、10℃/min、15℃/min和20℃/min不同升温速率下的石蜡、保形聚合物(PP与HDPE的混合物)、石蜡/保形聚合物和碳化钨(WC-10%Ni)粉末注射成形专用料的热解过程,采用Kissinger法和Flynn-Wall-OZAWA...采用热重分析法测定了在氮气气氛中5℃/min、10℃/min、15℃/min和20℃/min不同升温速率下的石蜡、保形聚合物(PP与HDPE的混合物)、石蜡/保形聚合物和碳化钨(WC-10%Ni)粉末注射成形专用料的热解过程,采用Kissinger法和Flynn-Wall-OZAWA法对4种专用料的热分解动力学进行分析,并用Coats-Redfern研究反应级数。结果表明,用Kissinger法分析不能很好地反映混合物的复杂的热解过程,不能支持碳化钨粉末注射成形一步热脱脂的工艺制定。用Flynn-Wall-OZAWA法分析,石蜡的热分解活化能在59~72 k J/mol,保形聚合物的热分解活化能在143~252 k J/mol,石蜡/保形聚合物的热分解活化能在60~240 k J/mol和WC-10%Ni的专用料的热分解活化能在93~220 k J/mol。用CoatsRedfern法分析,石蜡与保形聚合物的热解可用一级反应来描述,而石蜡/保形聚合物与WC-10%Ni的专用料的热解则适用3个连续一级反应来描述。展开更多
An effective and low-cost front-side anti-reflection(AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in p...An effective and low-cost front-side anti-reflection(AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in photovoltaic devices. In order to achieve high throughput fabrication of nanostructured flexible and anti-reflection films, large-scale, nano-engineered wafer molds were fabricated in this work. Additionally, to gain in-depth understanding of the optical and electrical performance enhancement with AR films on polycrystalline Si solar cells, both theoretical and experimental studies were performed. Intriguingly,the nanocone structures demonstrated an efficient light trapping effect which reduced the surface reflection of a solar cell by17.7% and therefore enhanced the overall electric output power of photovoltaic devices by 6% at normal light incidence. Notably, the output power improvement is even more significant at a larger light incident angle which is practically meaningful for daily operation of solar panels. The application of the developed AR films is not only limited to crystalline Si solar cells explored here, but also compatible with any types of photovoltaic technology for performance enhancement.展开更多
Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable device...Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable devices and building-integrated applications.However,the efficient harvesting of photons is the core hindrance towards efficient,flexible PV.Light management by nanostructures and nanomaterials has opened new pathways for sufficient solar energy harvesting.Nanostructures on top surfaces provide an efficient pathway for the propagation of light.Aside from suppressing incident light reflection,micro-structured back-reflectors reduce transmission via multiple reflections.Nanostructures themselves can be the absorber layer.Photovoltaics based on high-crystallinity nanostructured light absorbers demonstrate enhanced power conversion efficiency(PCE)and excellent mechanical flexibility.To acquire a deep understanding of the impacts of nanostructures,herein,a concise overview of the recent development in the design and application of nanostructures and nanomaterials for photovoltaics is summarized.展开更多
Flexible energy devices are the building blocks for next-generation wearable electronics.Flexible energy devices are expected to have multiple functions,such as energy conversion from light to electricity and vice ver...Flexible energy devices are the building blocks for next-generation wearable electronics.Flexible energy devices are expected to have multiple functions,such as energy conversion from light to electricity and vice versa,energy generation from triboelectric,energy storage and so on.These functions can be efficiently realized by solar cells,light-emitting diodes(LEDs),triboelectric nanogenerators(TENG),batteries and supercapacitors,etc.The flexible energy devices can be integrated into flexible,wearable,and/or portable platforms to enable wide application prospects in the fields of information,energy,medical care,national defense,etc.However,flexible energy devices face more challenges when compared to their rigid counterparts,which requires more breakthroughs and research efforts on fabrication techniques,materials innovation,novel structure designs,and deep physical understandings.展开更多
Quasi-two-dimensional(2D)Ruddlesden‒Popper(RP)halide perovskites,as a kind of emerged two-dimensional layered materials,have recently achieved great attentions in lasing materials field owing to their large exciton bi...Quasi-two-dimensional(2D)Ruddlesden‒Popper(RP)halide perovskites,as a kind of emerged two-dimensional layered materials,have recently achieved great attentions in lasing materials field owing to their large exciton binding energy,high emission yield,large optical gain,and wide-range tuning of optical bandgap.This review will introduce research progresses of RP halide perovskites for lasing applications in aspects of materials,photophysics,and devices with emphasis on emission and lasing properties tailored by the molecular composition and interface.The materials,structures and fabrications are introduced in the first part.Next,the optical transitions and amplified spontaneous emission properties are discussed from the aspects of electronic structure,exciton,gain dynamics,and interface tailoring.Then,the research progresses on lasing devices are summarized and several types of lasers including VCSEL,DFB lasers,microlasers,random lasers,plasmonic lasers,and polariton lasers are discussed.At last,the challenges and perspectives would be provided.展开更多
The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S...The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S thickness is usually less than 100 nm. However, pinholes in Cd S and non-conformal coverage of Cd S on transparent conducting oxide layer will cause shunting thus leading to device performance degradation and failure. In this paper, low-temperature and low-cost fabrication methods, i.e., chemical bath deposition and electrochemical deposition, were used to deposit Cd S and Cd Te, respectively. It was found that the yield of device was around 20 % due to shunting. In order to alleviate this problem, a compact layer of TiO2 was inserted between the fluorine-doped tin oxide and Cd S as a buffer layer. The thickness effect of TiO2 was studied and showed that devices with thin(20 nm thickness) TiO2 performed better than the counterparts with thick layers. It was discovered that device yield improved to 80 % and stability in air substantially improved with TiO2 layer.展开更多
The development of flexible photodetectors has received great attention for future optoelectronic applications including flexible image sensors, biomedical imaging, and smart, wearable systems. Previously omnidirectio...The development of flexible photodetectors has received great attention for future optoelectronic applications including flexible image sensors, biomedical imaging, and smart, wearable systems. Previously omnidirectional photodetectors were only achievable by integration of a hemispherical microlens assembly on multiple photodetectors. Herein, a hierarchical photodiode design of ZnO nanowires （NWs） on honeycomb-structured Si （H-Si） membranes is demonstrated to exhibit excellent omnidirectional light-absorption ability and thus maintain high photocurrents over broad spectral ranges （365 to 1,100 nm） for wide incident angles （0° to 70°）, which enabled broadband omnidirectional light detection in flexible photodetectors. Furthermore, the stress-relieving honeycomb pattern within the photodiode micromembranes provided photodetectors with excellent mechanical flexibility （10% decrease in photocurrent at a bending radius of 3 mm） and durability （minimal change in photocurrent over 10,000 bending cycles）. When employed in semiconductor thin films, the hierarchical NW/honeycomb heterostructure design acts as an efficient platform for various optoelectronic devices requiring mechanical flexibility and broadband omnidirectional light detection.展开更多
Volatile organic compounds(VOCs)are ubiquitous organic pollutants affecting atmospheric environment and human health.The development of new efficient and environmentally friendly materials utilizing photothermal syner...Volatile organic compounds(VOCs)are ubiquitous organic pollutants affecting atmospheric environment and human health.The development of new efficient and environmentally friendly materials utilizing photothermal synergistic catalysis for purification of VOCs is still challenging.Herein,we design and prepare a core–shell TiN@TiO_(2)nanostructure integrating with nanoscaled Pt(Pt/[TiN@TiO_(2)])by an attractive quenching method.The strong light-harvesting capability of Pt and TiN components improve light-to-heat utilization efficiency by their intrinsic surface plasmon resonance effect.The TiO_(2)component upon the surface and the coexisting coupling effect of Pt0 and Pt2+enhance the photocatalytic effect of the system.As a result,the catalytic performance is significantly improved with toluene(120 ppm)conversion of 100%under the gas hourly space velocity of 72,000 mL·g^(−1)·h^(−1)and light illumination of 500 mW·cm^(−2).The desired catalyst thus achieves highly efficient coupling effect of photocatalysis and light-to-heat conversion for promoting VOCs abatement.展开更多
Multilayered photovoltaic absorbers have triggered widespread attention for their unique structure and properties.However,multilayered materials in the randomly oriented polycrystalline thin-film lead to ineffective c...Multilayered photovoltaic absorbers have triggered widespread attention for their unique structure and properties.However,multilayered materials in the randomly oriented polycrystalline thin-film lead to ineffective carrier transport and collection,which hinders the process of achieving high-performance solar cells.Herein,this issue is tackled by producing the three-dimensional(3D)heterojunction BiI3 nanosheets(NSs)solar cells,which embed vertically aligned monocrystalline BiI3 NSs into spiro-OMeTAD.The preferred orientation of BiI3 NSs and large p-n junction areas of 3D heterojunction structure enable a strong light absorption and effective carrier transport and collection,and thus a power conversion efficiency(PCE)of 1.45%was achieved.Moreover,this PCE is the highest ever reported for BiI3 based solar cells to our best knowledge.Moreover,the nonencapsulated device remained 96%of the initial PCE after 24 h continuous one sun illumination at^70%humidity condition,and 82%of the initial PCE after 1-month storage at^30%humidity condition.展开更多
基金supported by Startup Funds from the Central Organization Department and the South China University of Technology(SCUT),as well as funds from the national natural science foundation of China(Grant No:U2001217)the Guangdong Science and Technology Program(2020B121201003,2019ZT08L075,2019QN01L118,2021A1515012545)the Fundamental Research Fund for the Central Universities,SCUT(2020ZYGXZR095).
文摘ABSTRACT Embedding submicrocavities is an effective approach to improve the light out-coupling efficiency(LOCE)for planar perovskite light-emitting diodes(PeLEDs).In this work,we employ phenethylammonium iodide(PEAI)to trigger the Ostwald ripening for the downward recrystallization of perovskite,resulting in spontaneous formation of buried submicrocavities as light output coupler.The simulation suggests the buried submicrocavities can improve the LOCE from 26.8 to 36.2%for near-infrared light.Therefore,PeLED yields peak external quantum efficiency(EQE)increasing from 17.3%at current density of 114 mA cm^(−2)to 25.5%at current density of 109 mA cm^(−2)and a radiance increasing from 109 to 487 W sr^(−1)m^(−2)with low rolling-off.The turn-on voltage decreased from 1.25 to 1.15 V at 0.1 W sr^(−1)m^(−2).Besides,downward recrystallization process slightly reduces the trap density from 8.90×10^(15)to 7.27×10^(15)cm^(−3).This work provides a self-assembly method to integrate buried output coupler for boosting the performance of PeLEDs.
文摘采用热重分析法测定了在氮气气氛中5℃/min、10℃/min、15℃/min和20℃/min不同升温速率下的石蜡、保形聚合物(PP与HDPE的混合物)、石蜡/保形聚合物和碳化钨(WC-10%Ni)粉末注射成形专用料的热解过程,采用Kissinger法和Flynn-Wall-OZAWA法对4种专用料的热分解动力学进行分析,并用Coats-Redfern研究反应级数。结果表明,用Kissinger法分析不能很好地反映混合物的复杂的热解过程,不能支持碳化钨粉末注射成形一步热脱脂的工艺制定。用Flynn-Wall-OZAWA法分析,石蜡的热分解活化能在59~72 k J/mol,保形聚合物的热分解活化能在143~252 k J/mol,石蜡/保形聚合物的热分解活化能在60~240 k J/mol和WC-10%Ni的专用料的热分解活化能在93~220 k J/mol。用CoatsRedfern法分析,石蜡与保形聚合物的热解可用一级反应来描述,而石蜡/保形聚合物与WC-10%Ni的专用料的热解则适用3个连续一级反应来描述。
基金supported by National Natural Science Foundation of China(Project No.51672231)Shen Zhen Science and Technology Innovation Commission(Project No.JCYJ20170818114107730)+1 种基金Hong Kong Research Grant Council(General Research Fund Project Nos.16237816,16309018)the support from the Center for 1D/2D Quantum Materials and the State Key Laboratory on Advanced Displays and Optoelectronics at HKUST
文摘An effective and low-cost front-side anti-reflection(AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in photovoltaic devices. In order to achieve high throughput fabrication of nanostructured flexible and anti-reflection films, large-scale, nano-engineered wafer molds were fabricated in this work. Additionally, to gain in-depth understanding of the optical and electrical performance enhancement with AR films on polycrystalline Si solar cells, both theoretical and experimental studies were performed. Intriguingly,the nanocone structures demonstrated an efficient light trapping effect which reduced the surface reflection of a solar cell by17.7% and therefore enhanced the overall electric output power of photovoltaic devices by 6% at normal light incidence. Notably, the output power improvement is even more significant at a larger light incident angle which is practically meaningful for daily operation of solar panels. The application of the developed AR films is not only limited to crystalline Si solar cells explored here, but also compatible with any types of photovoltaic technology for performance enhancement.
基金the National Natural Science Foundation of China(Project No.51672231)the Science and Technology Plan of Shenzhen(Project Nos.JCYJ20170818114107730,JCYJ20180306174923335)+2 种基金the General Research Fund(Project Nos.16309018,16214619)from the Hong Kong Research Grant Council.Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory(Project No.2020B1212030010)HKUST Fund of Nanhai(Grant No.FSNH-18FYTRI01)the Center for 1D/2D Quantum Materials and the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST and Foshan Innovative and Entrepreneurial Research Team Program(2018IT100031).
文摘Flexible solar cells are important photovoltaics(PV)technologies due to the reduced processing temperature,less material consumption and mechanical flexibility,thus they have promising applications for portable devices and building-integrated applications.However,the efficient harvesting of photons is the core hindrance towards efficient,flexible PV.Light management by nanostructures and nanomaterials has opened new pathways for sufficient solar energy harvesting.Nanostructures on top surfaces provide an efficient pathway for the propagation of light.Aside from suppressing incident light reflection,micro-structured back-reflectors reduce transmission via multiple reflections.Nanostructures themselves can be the absorber layer.Photovoltaics based on high-crystallinity nanostructured light absorbers demonstrate enhanced power conversion efficiency(PCE)and excellent mechanical flexibility.To acquire a deep understanding of the impacts of nanostructures,herein,a concise overview of the recent development in the design and application of nanostructures and nanomaterials for photovoltaics is summarized.
文摘Flexible energy devices are the building blocks for next-generation wearable electronics.Flexible energy devices are expected to have multiple functions,such as energy conversion from light to electricity and vice versa,energy generation from triboelectric,energy storage and so on.These functions can be efficiently realized by solar cells,light-emitting diodes(LEDs),triboelectric nanogenerators(TENG),batteries and supercapacitors,etc.The flexible energy devices can be integrated into flexible,wearable,and/or portable platforms to enable wide application prospects in the fields of information,energy,medical care,national defense,etc.However,flexible energy devices face more challenges when compared to their rigid counterparts,which requires more breakthroughs and research efforts on fabrication techniques,materials innovation,novel structure designs,and deep physical understandings.
基金Q.Z.acknowledges the funding support from the National Natural Science Foundation of China(Nos.52072006 and 51991344)the Natural Science Foundation of Beijing Municipality(No.JQ21004)+3 种基金F.L.acknowledges the funding support from the Hubei Province Science and Technology Major Project(No.2022AAA008)the National Natural Science Foundation of China(No.12374319)the Knowledge Innovation Program of Wuhan-Basic Research(No.2022010801010349)S.C.acknowledges the funding support from the Macao Science and Technology Development Fund(Nos.FDCT-0096/2020/A2 and FDCT-0082/2022/A2).
文摘Quasi-two-dimensional(2D)Ruddlesden‒Popper(RP)halide perovskites,as a kind of emerged two-dimensional layered materials,have recently achieved great attentions in lasing materials field owing to their large exciton binding energy,high emission yield,large optical gain,and wide-range tuning of optical bandgap.This review will introduce research progresses of RP halide perovskites for lasing applications in aspects of materials,photophysics,and devices with emphasis on emission and lasing properties tailored by the molecular composition and interface.The materials,structures and fabrications are introduced in the first part.Next,the optical transitions and amplified spontaneous emission properties are discussed from the aspects of electronic structure,exciton,gain dynamics,and interface tailoring.Then,the research progresses on lasing devices are summarized and several types of lasers including VCSEL,DFB lasers,microlasers,random lasers,plasmonic lasers,and polariton lasers are discussed.At last,the challenges and perspectives would be provided.
基金supported by Hong Kong Innovation Technology Commission project(ITS/117/13)Hong Kong Research Grants Council project(612113)+1 种基金Fundamental Research Project of Shenzhen Science & Technology Foundation(JCYJ20130402164725025)the International Collaboration Project of Shenzhen Science & Technology Foundation(GJHZ20130417170946221)
文摘The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S thickness is usually less than 100 nm. However, pinholes in Cd S and non-conformal coverage of Cd S on transparent conducting oxide layer will cause shunting thus leading to device performance degradation and failure. In this paper, low-temperature and low-cost fabrication methods, i.e., chemical bath deposition and electrochemical deposition, were used to deposit Cd S and Cd Te, respectively. It was found that the yield of device was around 20 % due to shunting. In order to alleviate this problem, a compact layer of TiO2 was inserted between the fluorine-doped tin oxide and Cd S as a buffer layer. The thickness effect of TiO2 was studied and showed that devices with thin(20 nm thickness) TiO2 performed better than the counterparts with thick layers. It was discovered that device yield improved to 80 % and stability in air substantially improved with TiO2 layer.
文摘The development of flexible photodetectors has received great attention for future optoelectronic applications including flexible image sensors, biomedical imaging, and smart, wearable systems. Previously omnidirectional photodetectors were only achievable by integration of a hemispherical microlens assembly on multiple photodetectors. Herein, a hierarchical photodiode design of ZnO nanowires （NWs） on honeycomb-structured Si （H-Si） membranes is demonstrated to exhibit excellent omnidirectional light-absorption ability and thus maintain high photocurrents over broad spectral ranges （365 to 1,100 nm） for wide incident angles （0° to 70°）, which enabled broadband omnidirectional light detection in flexible photodetectors. Furthermore, the stress-relieving honeycomb pattern within the photodiode micromembranes provided photodetectors with excellent mechanical flexibility （10% decrease in photocurrent at a bending radius of 3 mm） and durability （minimal change in photocurrent over 10,000 bending cycles）. When employed in semiconductor thin films, the hierarchical NW/honeycomb heterostructure design acts as an efficient platform for various optoelectronic devices requiring mechanical flexibility and broadband omnidirectional light detection.
基金the National Key Research and Development Program of China(No.2018YFA0209600)the Science and Technology Key Project of Guangdong Province,China(No.2020B010188002)+8 种基金Guangdong Innovative and Entrepreneurial Research Team Program(No.2019ZT08L075)Foshan Innovative and Entrepreneurial Research Team Program(No.2018IT100031)Guangdong Pearl River Talent Program(No.2019QN01L054)Shenzhen Peacock Plan(No.KQTD2016053015544057)Nanshan Pilot Plan(No.LHTD20170001)the Science and Technology Program of Guangzhou,China(No.202002030153)the Guangdong Science and Technology Program(No.2017B030314002)the National Natural Science Foundation of China(Nos.22176063 and 52000076)the Fundamental Research Funds for the Central Universities(No.2020ZYGXZR061).
文摘Volatile organic compounds(VOCs)are ubiquitous organic pollutants affecting atmospheric environment and human health.The development of new efficient and environmentally friendly materials utilizing photothermal synergistic catalysis for purification of VOCs is still challenging.Herein,we design and prepare a core–shell TiN@TiO_(2)nanostructure integrating with nanoscaled Pt(Pt/[TiN@TiO_(2)])by an attractive quenching method.The strong light-harvesting capability of Pt and TiN components improve light-to-heat utilization efficiency by their intrinsic surface plasmon resonance effect.The TiO_(2)component upon the surface and the coexisting coupling effect of Pt0 and Pt2+enhance the photocatalytic effect of the system.As a result,the catalytic performance is significantly improved with toluene(120 ppm)conversion of 100%under the gas hourly space velocity of 72,000 mL·g^(−1)·h^(−1)and light illumination of 500 mW·cm^(−2).The desired catalyst thus achieves highly efficient coupling effect of photocatalysis and light-to-heat conversion for promoting VOCs abatement.
基金General Research Fund,Grant/Award Number:16237816National Key Basic Research Program of China,Grant/Award Number:2015CB921600+5 种基金National Natural Science Foundation of China,Grant/Award Numbers:51672231,61574076Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20180330the Science and Technology Plan of Shenzhen,Grant/Award Number:JCYJ20170818114107730supported by the Science and Technology Plan of Shenzhen(JCYJ20170818114107730),National Natural Science Foundation of China(Project No.51672231),The General Research Fund(Project No.16237816)from the Hong Kong Research Grant Council,Natural Science Foundation of Jiangsu Province(Project No.BK20180330)National Natural Science Foundation of China(Project No.61574076)National Key Basic Research Program of China(Project No.2015CB921600).
文摘Multilayered photovoltaic absorbers have triggered widespread attention for their unique structure and properties.However,multilayered materials in the randomly oriented polycrystalline thin-film lead to ineffective carrier transport and collection,which hinders the process of achieving high-performance solar cells.Herein,this issue is tackled by producing the three-dimensional(3D)heterojunction BiI3 nanosheets(NSs)solar cells,which embed vertically aligned monocrystalline BiI3 NSs into spiro-OMeTAD.The preferred orientation of BiI3 NSs and large p-n junction areas of 3D heterojunction structure enable a strong light absorption and effective carrier transport and collection,and thus a power conversion efficiency(PCE)of 1.45%was achieved.Moreover,this PCE is the highest ever reported for BiI3 based solar cells to our best knowledge.Moreover,the nonencapsulated device remained 96%of the initial PCE after 24 h continuous one sun illumination at^70%humidity condition,and 82%of the initial PCE after 1-month storage at^30%humidity condition.
