Lead iodide single crystal was grown by physical vapor transport method.Two radiation detectors with different configurations were fabricated from the as-grown crystal.The electrical and y-ray response properties at r...Lead iodide single crystal was grown by physical vapor transport method.Two radiation detectors with different configurations were fabricated from the as-grown crystal.The electrical and y-ray response properties at room temperature of the both detectors were investigated.It is found that the dark resistivity of the detectors are respectively 3×10^（10）Ω·cm for bias electric field parallel to crystal c-axis（E//c） and 2×10~8Ω·cm for perpendicular to crystal c-axis（E⊥c）.The energy spectrum response measurement shows that both detectors were sensitive to ^（241） Am 59.5 keVγ-rays,and achieved a good energy resolution of 16.8%for the E⊥c-axis configuration detector with a full width at half maximum of 9.996 keV.展开更多
High-performance perovskite photodetectors with self-driven characteristic usually need electron/hole transport layers to extract carriers. However, these devices with transport layer structure are prone to result in ...High-performance perovskite photodetectors with self-driven characteristic usually need electron/hole transport layers to extract carriers. However, these devices with transport layer structure are prone to result in a poor perovskite/transport layer interface, which restricts the performance and stability of the device. To solve this problem, this work reports a novel device structure in which perovskite nanowires are in-situ prepared on PbI_(2), which serves as both a reaction raw material and efficient carrier extraction layer. By optimizing the thickness of PbI_(2), nanowire growth time, and ion exchange time, a selfdriven photodetector with an ITO/PbI_(2)/CsPbBr_(3)/carbon structure is constructed. The optimized device achieves excellent performance with the responsivity of 0.33 A/W, the detectivity of as high as 3.52 × 10^(13) Jones. Furthermore, the device can detect the light with its optical power lowered to 0.1 nW/cm^(2). This research provides a new method for preparing perovskite nano/micro devices with simple structure but excellent performance.展开更多
Introducing a stoichiometric excess of lead iodide(PbI_(2))in perovskite films has been demonstrated as an effective passivation strategy that can improve the power conversion efficiency(PCE)of perovskite solar cells(...Introducing a stoichiometric excess of lead iodide(PbI_(2))in perovskite films has been demonstrated as an effective passivation strategy that can improve the power conversion efficiency(PCE)of perovskite solar cells(PSCs),However,excess PbI_(2)is also known to accelerate the degradation of the perovskite layer.In this study,we show that this degradation primarily stems from the decomposition of PbI_(2)at the bottom of the perovskite film which is exposed to light We further show that when using a two-step spin coating deposition procedure,the excess PbI_(2)results from the decomposition of the perovskite during the annealing process rather than the presence of non-reacted PbI_(2).Finally,we demonstrate that the spatial distribution of PbI_(2)within the perovskite films can be controlled in a way that mitigates the PbI_(2)induced perovskite decomposition.In this manner,we produced devices exhibiting initial power conversion efficiencies over 25%,maintaining 98.6% after 1000 h of maximum power point tracking under continuous illumination.These findings offer valuable insights into achieving high performance PSCs through judicious process control using a two-step spin-coating procedure.展开更多
钙钛矿材料凭借其优异的性能可作为太阳能器件吸收层而备受关注。针对溶液法制备的钙钛矿吸收层薄膜残留PbI_(2)问题,提出了去除—钝化—退火3步法策略。首先采用正丁醇与环己烷(体积比为1∶4)的共溶剂对钙钛矿薄膜进行清洗,随后使用含...钙钛矿材料凭借其优异的性能可作为太阳能器件吸收层而备受关注。针对溶液法制备的钙钛矿吸收层薄膜残留PbI_(2)问题,提出了去除—钝化—退火3步法策略。首先采用正丁醇与环己烷(体积比为1∶4)的共溶剂对钙钛矿薄膜进行清洗,随后使用含有4-三氟甲氧基苯乙基碘化胺(phenethylammonium iodide with trifluoromethoxy groups,CF_(3)O-PEAI)的叔戊醇与环己烷(体积比为1∶4)的混合溶液钝化表面,最后进行退火处理。通过该策略不但能有效去除钙钛矿薄膜表面残留PbI_(2),且能使晶粒致密性更好、晶粒面积增大,整体优化了表面结晶形貌。制备的器件光电转换效率从17.93%提升至20.59%,相对提高了14.80%。研究结果表明,采用该策略在有效去除残留PbI_(2)的同时,还能较好地修复清洗后的表面.,最终使器件性能得到了提升。展开更多
P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,pero...P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,perovskite single crystal(C_(4)H_(9)NH_(3))_(2)PbI_(4)has been successfully synthesized via solution method.The obtained product was analyzed by single crystal X-ray diffraction.With the space group Pbca,orthorhombic(C_(4)H_(9)NH_(3))_(2)PbI_(4)layered perovskite structure consists of an extended two-dimensional network of corner-sharing PbI_(6)octahedron.Single layer perovskite sheets of distorted PbI_(6)octahedron alternated with protonated n-butylammonium cation bilayers,which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances.Density functional theory(DFT)simulations regarding the adsorption energy revealed that this organicinorganic hybrid perovskite compound has excellent selectivity toward p-xylene compared with other gases including C_(2)H_(5)OH,C_(6)H_(6),CH_(2)Cl_(2),HCHO,CH_(3)COCH_(3)and C_(7)H_(8).The calculation of electron density,density of states and electron density difference showed the sensing mechanism of p-C_(8)H_(10)is mainly derived from physical adsorption-desorption in view of electron transfer.展开更多
When focusing YAG laser pulses at 266nm into a heat-pipe oven containing PbI2 molecules vapor,four red line emissions at 626.0,619.8,613.7 and 621.8nm are observed.The photodissociation mechanism of PbI_(2) molecules ...When focusing YAG laser pulses at 266nm into a heat-pipe oven containing PbI2 molecules vapor,four red line emissions at 626.0,619.8,613.7 and 621.8nm are observed.The photodissociation mechanism of PbI_(2) molecules and the possible generation channels of these four line emissions are given.Moreover,the dependence of the emission at 626.0nm on incident laser energy and heat-pipe temperature is measured.The experimental observation is well supported by the photodissociation mechanism proposed by us.展开更多
The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would ...The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would increase with the test time extending,and the maximum efficiency is normally obtained after several days aging storage.Here,the relationship between enhanced device performance,excess PbI_(2)and its evolution in triple cation perovskite films of initial days was systematically explored.The Cs FAMA-PSCs are prepared by two-step methods under two environmental conditions,including in the glove box and the ambient air(30%humidity).After 7 days testing,the maximum PCE of PSCs under two conditions dramatically increased 12.4%and 12.2%,reached 21.68%and 21.89%,respectively.At initial days,the XRD peak intensities of perovskite phase gradually decreased and those corresponding to PbI_(2)increased.Along with time-resolved photoluminescence(TRPL)and kelvin probe force microscopy(KPFM),it was found that the defects were passivated with the evolution of PbI_(2).This work reveals the excess PbI_(2)and its evolution in perovskite film,which can further supplement the understanding of PbI_(2)defect passivation.展开更多
Lead iodide（PbI_2） films have been prepared by the electron beam evaporation technique,and their photoconductive response to visible light was investigated under different deposition and illumination conditions.It i...Lead iodide（PbI_2） films have been prepared by the electron beam evaporation technique,and their photoconductive response to visible light was investigated under different deposition and illumination conditions.It is found that the films＇ photoconductive response speed increases and the relative sensitivity decreases with the increase of substrate temperature due to the opposite requests for photo-carrier lifetime.Further,appropriately increasing the film＇s thickness and rising substrate temperature simultaneously can effectively balance the opposite demands.Under optimized conditions of a substrate temperature of 200℃,a source-substrate distance of 30 cm and a deposition time of 10 min,the prepared films exhibit the best response properties.In addition,the response to illumination with different wavelengths was also measured,revealing that the decline of response performance with increasing wavelength is due to the lower photon energy of incident light.展开更多
基金Project supported by the National Natural Science Foundation of China(No.50902012)the Natural Science Foundation of Sichuan Province,China(No.2009JY0087)
文摘Lead iodide single crystal was grown by physical vapor transport method.Two radiation detectors with different configurations were fabricated from the as-grown crystal.The electrical and y-ray response properties at room temperature of the both detectors were investigated.It is found that the dark resistivity of the detectors are respectively 3×10^（10）Ω·cm for bias electric field parallel to crystal c-axis（E//c） and 2×10~8Ω·cm for perpendicular to crystal c-axis（E⊥c）.The energy spectrum response measurement shows that both detectors were sensitive to ^（241） Am 59.5 keVγ-rays,and achieved a good energy resolution of 16.8%for the E⊥c-axis configuration detector with a full width at half maximum of 9.996 keV.
基金financially supported by the National Natural Science Foundation of China (51972101)the Research platforms and projects of Guangdong Universities in 2022 (2022ZDZX1028)Guangdong Provincial Key Laboratory Project (2023KSYS003)。
文摘High-performance perovskite photodetectors with self-driven characteristic usually need electron/hole transport layers to extract carriers. However, these devices with transport layer structure are prone to result in a poor perovskite/transport layer interface, which restricts the performance and stability of the device. To solve this problem, this work reports a novel device structure in which perovskite nanowires are in-situ prepared on PbI_(2), which serves as both a reaction raw material and efficient carrier extraction layer. By optimizing the thickness of PbI_(2), nanowire growth time, and ion exchange time, a selfdriven photodetector with an ITO/PbI_(2)/CsPbBr_(3)/carbon structure is constructed. The optimized device achieves excellent performance with the responsivity of 0.33 A/W, the detectivity of as high as 3.52 × 10^(13) Jones. Furthermore, the device can detect the light with its optical power lowered to 0.1 nW/cm^(2). This research provides a new method for preparing perovskite nano/micro devices with simple structure but excellent performance.
基金funding support from the National Key R&D Program of China(2021YFF0501900)the Excellent Young Scholar Fund from the National Natural Science Foundation of China(22122903)+1 种基金the Tianjin Distinguished Young Scholar Fund(20JCJQJC00260)support from the Tianchi Talent Program of Xinjiang Uygur Autonomous Region。
文摘Introducing a stoichiometric excess of lead iodide(PbI_(2))in perovskite films has been demonstrated as an effective passivation strategy that can improve the power conversion efficiency(PCE)of perovskite solar cells(PSCs),However,excess PbI_(2)is also known to accelerate the degradation of the perovskite layer.In this study,we show that this degradation primarily stems from the decomposition of PbI_(2)at the bottom of the perovskite film which is exposed to light We further show that when using a two-step spin coating deposition procedure,the excess PbI_(2)results from the decomposition of the perovskite during the annealing process rather than the presence of non-reacted PbI_(2).Finally,we demonstrate that the spatial distribution of PbI_(2)within the perovskite films can be controlled in a way that mitigates the PbI_(2)induced perovskite decomposition.In this manner,we produced devices exhibiting initial power conversion efficiencies over 25%,maintaining 98.6% after 1000 h of maximum power point tracking under continuous illumination.These findings offer valuable insights into achieving high performance PSCs through judicious process control using a two-step spin-coating procedure.
文摘钙钛矿材料凭借其优异的性能可作为太阳能器件吸收层而备受关注。针对溶液法制备的钙钛矿吸收层薄膜残留PbI_(2)问题,提出了去除—钝化—退火3步法策略。首先采用正丁醇与环己烷(体积比为1∶4)的共溶剂对钙钛矿薄膜进行清洗,随后使用含有4-三氟甲氧基苯乙基碘化胺(phenethylammonium iodide with trifluoromethoxy groups,CF_(3)O-PEAI)的叔戊醇与环己烷(体积比为1∶4)的混合溶液钝化表面,最后进行退火处理。通过该策略不但能有效去除钙钛矿薄膜表面残留PbI_(2),且能使晶粒致密性更好、晶粒面积增大,整体优化了表面结晶形貌。制备的器件光电转换效率从17.93%提升至20.59%,相对提高了14.80%。研究结果表明,采用该策略在有效去除残留PbI_(2)的同时,还能较好地修复清洗后的表面.,最终使器件性能得到了提升。
基金financially supported by the Natural Science Foundation of Hebei(Nos.F2020202027 and F2020202067)the Major National Science and Technology Special Projects(No.2016ZX02301003-004-007)+1 种基金the National Natural Science Foundation of China(No.21271139)the Natural Science Foundation of Tianjin(No.17JCTPJC54500)。
文摘P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,perovskite single crystal(C_(4)H_(9)NH_(3))_(2)PbI_(4)has been successfully synthesized via solution method.The obtained product was analyzed by single crystal X-ray diffraction.With the space group Pbca,orthorhombic(C_(4)H_(9)NH_(3))_(2)PbI_(4)layered perovskite structure consists of an extended two-dimensional network of corner-sharing PbI_(6)octahedron.Single layer perovskite sheets of distorted PbI_(6)octahedron alternated with protonated n-butylammonium cation bilayers,which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances.Density functional theory(DFT)simulations regarding the adsorption energy revealed that this organicinorganic hybrid perovskite compound has excellent selectivity toward p-xylene compared with other gases including C_(2)H_(5)OH,C_(6)H_(6),CH_(2)Cl_(2),HCHO,CH_(3)COCH_(3)and C_(7)H_(8).The calculation of electron density,density of states and electron density difference showed the sensing mechanism of p-C_(8)H_(10)is mainly derived from physical adsorption-desorption in view of electron transfer.
基金Supported by the National Natural Science Foundation of China for Distinguished Young Scholars(19825110)National High Technology 410 Project.
文摘When focusing YAG laser pulses at 266nm into a heat-pipe oven containing PbI2 molecules vapor,four red line emissions at 626.0,619.8,613.7 and 621.8nm are observed.The photodissociation mechanism of PbI_(2) molecules and the possible generation channels of these four line emissions are given.Moreover,the dependence of the emission at 626.0nm on incident laser energy and heat-pipe temperature is measured.The experimental observation is well supported by the photodissociation mechanism proposed by us.
基金the financial support from the Young Scholars Development Fund of SWPU(201699010017)the Sichuan Science and Technology Program(2018JY0015)+1 种基金the National Nature Science Foundation of China(61774022)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant(2020LKSFG01A)。
文摘The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would increase with the test time extending,and the maximum efficiency is normally obtained after several days aging storage.Here,the relationship between enhanced device performance,excess PbI_(2)and its evolution in triple cation perovskite films of initial days was systematically explored.The Cs FAMA-PSCs are prepared by two-step methods under two environmental conditions,including in the glove box and the ambient air(30%humidity).After 7 days testing,the maximum PCE of PSCs under two conditions dramatically increased 12.4%and 12.2%,reached 21.68%and 21.89%,respectively.At initial days,the XRD peak intensities of perovskite phase gradually decreased and those corresponding to PbI_(2)increased.Along with time-resolved photoluminescence(TRPL)and kelvin probe force microscopy(KPFM),it was found that the defects were passivated with the evolution of PbI_(2).This work reveals the excess PbI_(2)and its evolution in perovskite film,which can further supplement the understanding of PbI_(2)defect passivation.
基金Project supported by the National Natural Science Foundation of China(No.50902012)the Natural Science Foundation of Sichuan Province,China(No.2009JY0087).
文摘Lead iodide（PbI_2） films have been prepared by the electron beam evaporation technique,and their photoconductive response to visible light was investigated under different deposition and illumination conditions.It is found that the films＇ photoconductive response speed increases and the relative sensitivity decreases with the increase of substrate temperature due to the opposite requests for photo-carrier lifetime.Further,appropriately increasing the film＇s thickness and rising substrate temperature simultaneously can effectively balance the opposite demands.Under optimized conditions of a substrate temperature of 200℃,a source-substrate distance of 30 cm and a deposition time of 10 min,the prepared films exhibit the best response properties.In addition,the response to illumination with different wavelengths was also measured,revealing that the decline of response performance with increasing wavelength is due to the lower photon energy of incident light.
