Improving Charge Carrier Delocalization in Perovskite Quantum Dots by Surface Passivation with Conductive Aromatic Ligands
Improving Charge Carrier Delocalization in Perovskite Quantum Dots by Surface Passivation with Conductive Aromatic Ligands
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DOI：
10.1021/acsenergylett.8b01754
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发表时间：
2018-12-01
影响因子：
22
通讯作者：
Zhang, Jin Z.
中科院分区：
文献类型：
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作者：
Vickers, Evan T.;Graham, Thomas A.;Zhang, Jin Z.
长链饱和烃和烷氧基硅烷是常用于钝化钙钛矿量子点（PQD）以增强其稳定性和光学性质的配体。然而，这些封端配体的绝缘性质产生电子能垒并阻碍粒子间电子耦合，从而限制了器件应用。解决这个问题的一个策略是使用短的导电芳族配体，其允许电子波函数从PQD离域，这又通过降低能垒促进PQD之间的电荷传输。这用使用苄胺（BZA）和苯甲酸（BA）封端配体制备的甲基铵溴化铅（MAPbBr（3））QD证明。优化的BZA-BA-MAPbBr（3）QD是高度稳定的，并且显示出非常高的光致发光（PL）量子产率（QY）（86%）。更重要的是，BZA-BA-MAPbBr（3）QD膜与具有绝缘配体的PQD相比具有更高的电导率和载流子寿命以及更有效的电荷提取，如电化学测量和瞬态光电流和光电压光谱所示。
Long-chain saturated hydrocarbons and alkoxysilanes are ligands that are commonly used to passivate perovskite quantum dots (PQDs) to enhance their stability and optical properties. However, the insulating nature of these capping ligands creates an electronic energy barrier and impedes interparticle electronic coupling, thereby limiting device applications. One strategy to solve this problem is the use of short conductive aromatic ligands that allow delocalization of the electronic wave function from the PQDs, which, in turn, facilitates charge transport between PQDs by lowering the energy barrier. This is demonstrated with methylammonium lead bromide (MAPbBr(3)) QDs prepared using benzylamine (BZA) and benzoic acid (BA) capping ligands. Optimized BZA-BA-MAPbBr(3) QDs are highly stable and show very high photoluminescence (PL) quantum yield (QY) (86%). More importantly, the BZA-BA-MAPbBr(3) QD film exhibits higher conductivity and carrier lifetime and more efficient charge extraction compared to PQDs with insulating ligands, as indicated by electrochemical measurements and transient photocurrent and photovoltage spectroscopy.