Enhancing Charge Carrier Delocalization in Perovskite Quantum Dot Solids with Energetically Aligned Conjugated Capping Ligands
Enhancing Charge Carrier Delocalization in Perovskite Quantum Dot Solids with Energetically Aligned Conjugated Capping Ligands
复制标题
DOI：
10.1021/acsenergylett.0c00093
复制
发表时间：
2020-03-13
影响因子：
22
通讯作者：
Zhang, Jin Z.
中科院分区：
文献类型：
--
作者：
Vickers, Evan T.;Enlow, Emily E.;Zhang, Jin Z.
与体相钙钛矿相比，钙钛矿量子点(PQD)固体中的电荷输运是有限的。为了解决这个问题，我们使用能量定向的封端配体来制备甲基溴化铵铅(MAPbBr3)PQD，以提高PQD固体的表面载流子密度。反式肉桂酸(TCA)及其衍生物通过供电子或吸电子基团来调节能级，被用作钝化激子离域配体(EDL)以减小相对于PQD核心的能隙。3，3-二苯丙胺(DPPA)配体通过pi-pi堆积分子间相互作用，减缓电荷捕获和非辐射衰变，稳定了PQD表面的EDL。结合使用EDLS和DPPA钝化可以提高PQD固体中载流子的光致发光(PL)、量子产率(QY)(90%)、光导性、提取、迁移率、传输时间和寿命。展示了基于PQD的发光二极管(LED)原型，开启电压低至2.5V。
Compared to bulk perovskites, charge transport in perovskite quantum dot (PQD) solids is limited. To address this issue, energetically aligned capping ligands were used to prepare methylammonium lead bromide (MAPbBr(3)) PQDs toward enhancing surface charge carrier density in PQD solids. Trans-cinnamic acid (TCA) and its derivates, functionalized with electron-donating or electron-withdrawing groups to modulate energy levels, are used as passivating exciton-delocalizing ligands (EDLs) to decrease the energy gap with respect to the PQD core. 3,3-Diphenylpropylamine (DPPA) ligand is shown to stabilize EDLs on the PQD surface through pi-pi stacking intermolecular interaction, mitigating charge trapping and nonradiative decay. Passivation using EDLs in combination with DPPA increases the photoluminescence (PL) quantum yield (QY) (90%), photoconductivity, extraction, mobility, transport time, and lifetime of charge carriers in PQD solids. Prototype PQD-based light-emitting diodes (LEDs) were demonstrated with a low turn-on voltage of 2.5 V.