Rubrene thin films are deposited on quartz substrates and silver nanoparticles （Ag NPs） films by the thermal evapo- ration technique. The optical properties of rubrene thin film are investigated in a spectral range ...Rubrene thin films are deposited on quartz substrates and silver nanoparticles （Ag NPs） films by the thermal evapo- ration technique. The optical properties of rubrene thin film are investigated in a spectral range of 190 nm-1600 nm. The analysis of the absorption coefficient （a） reveals direct allowed transition with a corresponding energy of 2.24 eV. The photoluminescence （PL） peak of the mbrene thin film is observed to be at 563 nm （2.21 eV）. With the use ofAg NPs which are fabricated by radio-frequency （RF） rnagnetron sputtering on the quartz, the PL intensity is 8.5 times that of as-deposited rubrene thin film. It is attributed to the fact that the surface plasmon enhances the photoluminescence.展开更多
Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respective...Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respectively. Highly crystalline ZnO nanorods were obtained by electrochemical deposition in a chloride medium. Additionally, rubrene interlayer was able to passivate or cover the grain boundaries of perovskite film effectively that led to reduced leakage current. A perovskite solar cell optimized with ZnO nanorods and rubrene：P3HT bilayer achieved a maximum efficiency of 4.9% showing reduced hysteresis behavior compared with the device having P3HT as the only hole-transporting layer. The application of longer nanorods led to better perovskite infiltration and shorter charge carrier path length. These results highlight the potential of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as charge selective layers for efficient perovskite solar cells.展开更多
Organic/inorganic hybrid van der Waals heterostructure with an atomically abrupt interface has attracted great research interests within the field of multifunctional electronic and optoelectronic devices.The integrati...Organic/inorganic hybrid van der Waals heterostructure with an atomically abrupt interface has attracted great research interests within the field of multifunctional electronic and optoelectronic devices.The integration of organic rubrene films with inorganic Si semiconductors can avoid the atomic mutual-diffusion at the interface,and provide the possibility of forming two-dimensional van der Waals heterojunction accompanied with the type-II energy band alignment,due to the transfer behaviors of majority carriers at the interface.In this study,the high-quality rubrene/Si van der Waals heterostructure with an electronically abrupt junction was prepared,and a self-powered photodetector was then constructed based on this hybrid heterojunction.The photodetector demonstrated an excellent switching response to the 1064 nm monochromatic light with large on/off current ratio of 7.0×10^(3),the maximum photocurrent of 14.62 m A,the maximum responsivity of 2.07 A/W,the maximum detectivity of 2.9×10^(11)Jones,and a fast response time of 13.0μs.This study offers important guidance for preparing high-quality rubrene/Si hybrid van der Waals heterostructure with desirable band alignment,and the designed heterojunction photodetector has an important application prospect in the field of multifunctional optoelectronics.展开更多
Singlet fission(SF)is an appealing process where one photoexcited singlet transforms to two triplets,which can overcome thermalization energy loss and improve solar cell efficiency.However,it remains unclear how inter...Singlet fission(SF)is an appealing process where one photoexcited singlet transforms to two triplets,which can overcome thermalization energy loss and improve solar cell efficiency.However,it remains unclear how intermolecular coupling,which is subject to molecular stacking,controls SF pathways and dynamics.Here,we prepared polymorph rubrene single crystals with different stacking geometries,including orthorhombic(Orth.),triclinic(Tri.),and monoclinic(Mono.)phases.By micro-area ultrafast spectroscopy,we find that Orth.and Tri.phases with closerπ-πstacking exhibit co-existing coherent and incoherent SF channels while loosely stacked Mono.phase shows only incoherent SF.Furthermore,incoherent SF is thermally activated in Orth.but barrierless in Mono.and Tri.phases.Quantum mechanical calculation reveals that different electronic coupling strength in different phases leads to different SF dynamics.This study demonstrates that molecular stacking governs SF dynamics through electronic coupling,providing guidance for designing efficient SF materials via crystal structural engineering.展开更多
基金Project supported by the Funding for the Development Project of Beijing Municipal Education Commission of Science and Technology,China(Grant No.KZ201410005008)the Natural Science Foundation of Beijing City,China(Grant No.4102014)the Graduate Science Fund of the Beijing University of Technology,China(Grant No.ykj-2013-9835)
文摘Rubrene thin films are deposited on quartz substrates and silver nanoparticles （Ag NPs） films by the thermal evapo- ration technique. The optical properties of rubrene thin film are investigated in a spectral range of 190 nm-1600 nm. The analysis of the absorption coefficient （a） reveals direct allowed transition with a corresponding energy of 2.24 eV. The photoluminescence （PL） peak of the mbrene thin film is observed to be at 563 nm （2.21 eV）. With the use ofAg NPs which are fabricated by radio-frequency （RF） rnagnetron sputtering on the quartz, the PL intensity is 8.5 times that of as-deposited rubrene thin film. It is attributed to the fact that the surface plasmon enhances the photoluminescence.
文摘Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respectively. Highly crystalline ZnO nanorods were obtained by electrochemical deposition in a chloride medium. Additionally, rubrene interlayer was able to passivate or cover the grain boundaries of perovskite film effectively that led to reduced leakage current. A perovskite solar cell optimized with ZnO nanorods and rubrene：P3HT bilayer achieved a maximum efficiency of 4.9% showing reduced hysteresis behavior compared with the device having P3HT as the only hole-transporting layer. The application of longer nanorods led to better perovskite infiltration and shorter charge carrier path length. These results highlight the potential of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as charge selective layers for efficient perovskite solar cells.
基金the National Natural Science Foundation of China(Grant Nos.11604228,11774208,and 11974222)the Science and Technology Planning Foundation of Shandong Province,China(Grant No.J18KA219)。
文摘Organic/inorganic hybrid van der Waals heterostructure with an atomically abrupt interface has attracted great research interests within the field of multifunctional electronic and optoelectronic devices.The integration of organic rubrene films with inorganic Si semiconductors can avoid the atomic mutual-diffusion at the interface,and provide the possibility of forming two-dimensional van der Waals heterojunction accompanied with the type-II energy band alignment,due to the transfer behaviors of majority carriers at the interface.In this study,the high-quality rubrene/Si van der Waals heterostructure with an electronically abrupt junction was prepared,and a self-powered photodetector was then constructed based on this hybrid heterojunction.The photodetector demonstrated an excellent switching response to the 1064 nm monochromatic light with large on/off current ratio of 7.0×10^(3),the maximum photocurrent of 14.62 m A,the maximum responsivity of 2.07 A/W,the maximum detectivity of 2.9×10^(11)Jones,and a fast response time of 13.0μs.This study offers important guidance for preparing high-quality rubrene/Si hybrid van der Waals heterostructure with desirable band alignment,and the designed heterojunction photodetector has an important application prospect in the field of multifunctional optoelectronics.
基金National Natural Science Foundation of China,Grant/Award Numbers:22273084,22073045。
文摘Singlet fission(SF)is an appealing process where one photoexcited singlet transforms to two triplets,which can overcome thermalization energy loss and improve solar cell efficiency.However,it remains unclear how intermolecular coupling,which is subject to molecular stacking,controls SF pathways and dynamics.Here,we prepared polymorph rubrene single crystals with different stacking geometries,including orthorhombic(Orth.),triclinic(Tri.),and monoclinic(Mono.)phases.By micro-area ultrafast spectroscopy,we find that Orth.and Tri.phases with closerπ-πstacking exhibit co-existing coherent and incoherent SF channels while loosely stacked Mono.phase shows only incoherent SF.Furthermore,incoherent SF is thermally activated in Orth.but barrierless in Mono.and Tri.phases.Quantum mechanical calculation reveals that different electronic coupling strength in different phases leads to different SF dynamics.This study demonstrates that molecular stacking governs SF dynamics through electronic coupling,providing guidance for designing efficient SF materials via crystal structural engineering.
文摘在二氧化硅衬底上依次真空沉积p-六联苯(p-6P)和酞菁铜(CuPc)构成双异质诱导层,研究了不同衬底温度下双异质诱导层对红荧烯薄膜形貌的影响,以及红荧烯分子在双异质诱导层上的生长过程.分析发现,第二诱导层酞菁铜的局部有序性对红荧烯薄膜的结晶度有直接影响.随着衬底温度的升高,酞菁铜薄膜有序区域面积增大,红荧烯的棒状晶粒也逐渐增大.当酞菁铜和红荧烯的衬底温度均为90℃,红荧烯蒸镀厚度为20 nm时,红荧烯薄膜形成高度有序、内部连接及具有特定方向的棒状晶畴.利用X射线衍射(XRD)和透射电子显微镜(TEM)分析了红荧烯薄膜的晶体结构,发现经过双异质诱导后的红荧烯薄膜转变为多晶形态.另外,红荧烯薄膜晶体管性能也明显提高,开态电流提高了约3个数量级,迁移率提高了30倍,阈值电压降低了20 V.
