Surface‐Engineered Ti<sub>3</sub>C<sub>2</sub>T<i><sub>x</sub></i> with Tunable Work Functions for Highly Efficient Polymer Solar Cells
Chun‐Li Hou, Chengwen Huang, Huangzhong Yu, Shengwei Shi
Abstract
Abstract Ti 3 C 2 T x , as a newly investigated 2D material, has gained great attention owing to its metallic conductivity, tunable work function ( W F ), and unique electrical property. However, its W F can be further adjusted to meet the needs of optoelectronic devices. Here, surface‐engineered Ti 3 C 2 T x is fabricated with tunable W F by treating with ethanolamine and rhodium chloride (RhCl 3 ). Ethanolamine treated Ti 3 C 2 T x can induce the chemical adsorption of NH 2 on Ti 3 C 2 T x with hydrogen‐bonding, which causes the decreased W F , while chemical doping with RhCl 3 leads to the improvement of W F , which is achieved by the downshift of Femi level of Ti 3 C 2 T x . Moreover, the ethanolamine and RhCl 3 can effectively passivate the vacancies of Ti. As such, the surface‐engineered Ti 3 C 2 T x is more suitable as buffer layer for polymer solar cells (PSCs) by enhancing the interfacing characteristics of the Ti 3 C 2 T x /active layer. The PSCs with engineered Ti 3 C 2 T x for electron or hole transport layers can exhibit a power conversion efficiency of 15.88% or 15.54%. These efficiencies can be compared with those of devices with a conventional transport layer. This work provides a facile strategy to realize the work function tunability of Ti 3 C 2 T x , and also shows that the tuned Ti 3 C 2 T x has a certain application prospect in photovoltaic devices.