Lee Sang-Hun, Kim Jun Young, Choi Sinil, Lee Yongjun, Lee Kwang-Sup, Kim Jeongyong, Joo Jinsoo
Department of Physics, Korea University, Seoul 02841, Republic of Korea.
Department of Advanced Materials, Hannam University, Daejeon 34054, Republic of Korea.
ACS Appl Mater Interfaces. 2020 Jun 3;12(22):25159-25167. doi: 10.1021/acsami.0c04924. Epub 2020 May 22.
Perovskite CsPbX (X = Br, Cl, and I) nanostructures have been intensively studied as they are luminescent, photovoltaic, and photosensitizing active materials. Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) with MX (M = Mo, W; X = S, Se, Te, etc.) structures have been used in flexible optoelectronic devices. In this study, perovskite green-light-emitting CsPbBrI quantum dots (QDs) and blue-light-emitting CsPb(Cl/Br)-QDs are utilized to enhance the photoresponsive characteristics of 2D MSe (M = Mo and W)-based field-effect transistors (FETs). From laser confocal microscopy photoluminescence (PL) experiments, PL quenching of the perovskite CsPb(Cl/Br)-QDs and CsPbBrI-QDs is observed after hybridization with MoSe and WSe layers, respectively, which reflects the charge-transfer effect. According to the characteristics of the FETs based on the WSe, MoSe, WSe/CsPbBrI-QDs hybrid, and MoSe/CsPb(Cl/Br)-QDs hybrid, the p-channel current (with hole mobility) is considerably decreased after the hybridization with the QDs. Notably, under incident light, the n-channel photocurrent and photoresponsivity of the FET are substantially increased, and the threshold voltage is negatively shifted owing to the hybridization with the perovskite QDs. The results show that the photosensitive n-type doping effect on the 2D MoSe and WSe nanosystems originates from the photogating effect by the trap states after the hybridization with various perovskite CsPbX-QDs.
钙钛矿CsPbX（X = Br、Cl和I）纳米结构因其具有发光、光伏和光敏活性材料的特性而受到广泛研究。具有MX（M = Mo、W；X = S、Se、Te等）结构的二维（2D）过渡金属二卤化物（TMDCs）已被用于柔性光电器件。在本研究中，利用钙钛矿绿光发射CsPbBrI量子点（QDs）和蓝光发射CsPb(Cl/Br)-QDs来增强基于二维MSe（M = Mo和W）的场效应晶体管（FET）的光响应特性。通过激光共聚焦显微镜光致发光（PL）实验，分别观察到钙钛矿CsPb(Cl/Br)-QDs和CsPbBrI-QDs与MoSe和WSe层杂交后的PL猝灭，这反映了电荷转移效应。根据基于WSe、MoSe、WSe/CsPbBrI-QDs杂化物和MoSe/CsPb(Cl/Br)-QDs杂化物的FET的特性，与量子点杂交后，p沟道电流（具有空穴迁移率）显著降低。值得注意的是，在入射光下，FET的n沟道光电流和光响应率大幅增加，并且由于与钙钛矿量子点杂交，阈值电压负向偏移。结果表明，二维MoSe和WSe纳米系统上的光敏n型掺杂效应源于与各种钙钛矿CsPbX-QDs杂交后陷阱态的光门控效应。
