Abstract：
Due to the large distance or weak electronic conjugation between adjacent Bi-I octahedrons, the charge transport in the low-dimensional bismuth-based hybrid perovskites is impeded and thus hinders their future developments. In this work, A-site cation engineering by monoamine BZA (benzylamine) and diamine 3-AMP (3-(aminomethyl)pyridine) has been demonstrated as an efficient strategy to regulate the corresponding activation energy of ionic migration and carrier transport capacity. Given the higher polarity of 3-AMP than BZA, producing a more efficient dielectric screening effect, it gives rise to obtaining the small exciton binding energy (50 meV) and low defect states (3.53×109 cm-3 ). The reduced distance of adjacent Bi-I octahedrons by the bilateral anchoring of the 3-AMP2+ diamine cation enhances both electronic conjugation and charge transport performance. Therefore, the photodetector for (3-AMP)BiI5 SC shows a 243-fold increase in on/off ratio compared with the (BZA)3 BiI6 SC.
摘要：
由于相邻Bi-I八面体之间的距离大或电子共轭弱，低维铋基混合钙钛矿中的电荷传输受到阻碍，从而阻碍了它们的未来发展。在这项工作中,通过单胺BZA（苄胺）和二胺3-AMP（3-（氨基甲基）吡啶）进行的A位阳离子工程已被证明是调节离子迁移和载流子传输能力的相应活化能的有效策略。鉴于3-AMP的极性高于BZA，产生更有效的介电屏蔽效果，它导致获得小的激子结合能（50meV）和低缺陷态（3.53×109cm-3）。通过3-AMP2二胺阳离子的双侧锚定减少了相邻Bi-I八面体的距离，从而增强了电子共轭和电荷传输性能。因此,与（BZA）3BiI6SC相比，（3-AMP）BiI5SC的光电探测器的开/关比增加了243倍。
