基于全溶液法制备的SnO_(2)/1D-CsAg_(2)I_(3)异质结的高灵敏自驱动可见光盲紫外探测器

All solution-processed SnO_(2)/1D-CsAg_(2)I_(3) heterojunction for highsensitivity self-powered visible-blind UV photodetector

低维非铅金属卤化物材料因其优异的光电特性在可见光盲紫外探测领域具有很大的潜力.本文通过吡啶添加剂辅助一步溶液法成功制备了高质量类钙钛矿CsAg_(2)I_(3)薄膜,该薄膜展示出p型及202 meV低激子结合能(Eb).其Eb甚至和2D铅卤钙钛矿相当,有利于光生载流子分离.此外,探索了基于type-Ⅱ型n-p异质结SnO_(2)/CsAg_(2)I_(3)的自驱动紫外探测器,其中4.13 eV宽带隙、0.214 eV低Urbach能量的SnO_(2)的引入抑制了持续光电导效应.所制备的探测器件具有高灵敏特性及在可见光盲紫外探测器中超快的响应时间(47/74μs),大致快于当前CsAg_(2)I_(3)探测器数值的两个数量级.其响应度和探测率分别高达0.032 A W^(-1)和1.2×10^(11)Jones.此外,异质结>90%高可见光透光性展现出优越的可见光盲特性.这种优异的器件性能、可溶液法制备及长期稳定性为未来可见光盲、自驱动、稳定、环保的商用紫外探测器的制备提供了新思路.

Low-dimensional lead-free metal halides have shown considerable potential for visible-blind ultraviolet(UV)photodetectors(PDs)owing to their extraordinary optoelectronic properties.Herein,a high-quality perovskite-like CsAg_(2)I_(3) thin film was successfully fabricated via the pyridine additive-assisted one-step solution method,and it exhibited an intrinsic p-type behavior and possessed a low exciton binding energy of 202 meV,which was even comparable to low-dimensional lead halide perovskite counterpart and thus favored the separation of photogenerated carriers.Additionally,a type-II n-p heterojunction of SnO_(2)/CsAg_(2)I_(3) for a self-powered UV PD was configured and investigated experimentally and theoretically.A 4.13-eV-wide-bandgap SnO_(2) with an extremely low Urbach energy of 0.214 eV was obtained to suppress the persistent photoconductivity effect.The resulting device exhibited pronounced sensitivity with an ultrafast response time of 47/74μs,which is outstanding among visible-blind UV PDs and two orders of magnitude lower than previously reported CsAg_(2)I_(3)-based UV PDs.The responsivity and detectivity were as high as 0.032 A W^(−1) and 1.2×10^(11) Jones,respectively.Furthermore,the highly transparent(>90%)heterojunction for visible light illustrated the superior visible-blind characteristics.The remarkable device performance,solution-processability,and long-term stability reveal a promising strategy for the design of commercial UV PDs that are visible-blind,self-powered,stable,and nontoxic.