Ti₃C₂T<i>_x</i> MXene‐Assisted CuBO₂ Hole Transport Layer for High‐Performance Ultraviolet Photodetectors

Abstract

Abstract The efficient separation and extraction of holes can be attributed to the favorable properties possessed by the hole transport layer (HTL). Herein, a novel solution‐processable hybrid HTL based on CuBO 2 and Ti 3 C 2 T x MXene (CuBO 2 @MXene) is developed to enhance the performance of ultraviolet photodetectors (UV PDs). By optimizing the ratio of Ti 3 C 2 T x MXene to CuBO 2 , the optimized responsivity and detectivity of the UV PDs based on the composite HTL have achieved 184 mA W −1 and 2.88 × 10 13 cm Hz 1/2 W −1 in self‐powered mode, respectively, and even up to 3.25 × 10 4 mA W −1 at −1.5 V. This significant improvement in device performance can be attributed to the interlaced architecture of CuBO 2 @MXene, which ameliorates hole mobility and charge extraction capability while reducing the trap state density of the HTL. The built‐in electric field of the TiO 2 /CuBO 2 heterojunction is strengthened by the incorporation of Ti 3 C 2 T x MXene, thereby significantly reinforcing the photovoltaic effect. Moreover, the lower thermal conductivity of CuBO 2 @MXene suppresses its pyroelectric effect, weakening the blocking effect of the thermoelectric potential on hole transport and ultimately leading to a remarkable boost in the output current. These results indicate the promising potential of the hybrid CuBO 2 @MXene HTL for constructing high‐performance optoelectronic devices.