Interface Engineering to Drive High‐Performance MXene/PbS Quantum Dot NIR Photodiode
Yunxiang Di, Kun Ba, Yan Chen, Xudong Wang, Mingqing Zhang, Xinning Huang, Yi Long, Mengdi Liu, Shukui Zhang, Weiyi Tang, Zhangcheng Huang, Tie Lin, Hong Shen, Xiangjian Meng, Meikang Han, Qi Liu, Jianlu Wang
Abstract
Abstract The realization of a controllable transparent conducting system with selective light transparency is crucial for exploring many of the most intriguing effects in top‐illuminated optoelectronic devices. However, the performance is limited by insufficient electrical conductivity, low work function, and vulnerable interface of traditional transparent conducting materials, such as tin‐doped indium oxide. Here, it is reported that two‐dimensional (2D) titanium carbide (Ti 3 C 2 T x ) MXene film acts as an efficient transparent conducting electrode for the lead sulfide (PbS) colloidal quantum dots (CQDs) photodiode with controllable near infrared transmittance. The solution‐processed interface engineering of MXene and PbS layers remarkably reduces the interface defects of MXene/PbS CQDs and the carrier concentration in the PbS layer. The stable Ti 3 C 2 T x /PbS CQDs photodiodes give rise to a high specific detectivity of 5.51 × 10 12 cm W −1 Hz 1/2 , a large dynamic response range of 140 dB, and a large bandwidth of 0.76 MHz at 940 nm in the self‐powered state, ranking among the most exceptional in terms of comprehensive performance among reported PbS CQDs photodiodes. In contrast with the traditional photodiode technologies, this efficient and stable approach opens a new horizon to construct widely used infrared photodiodes with CQDs and MXenes.