Water soluble nanocrystals (NCs) are promising materials in aqueous‐processed solar cells because of their high extinction coefficient, low‐cost, and favorable photoelectric characteristics. However, the power conversion efficiency (PCE) of the present aqueous‐processed NC solar cells is restricted by the short depletion region of the active layer and limited Fermi level offset between NCs and the electron transport layer. Herein, these issues are effectively addressed by preparing Cd_xZn_1–xTe NCs capped with 2‐aminoethanethiol hydrochloride. The introduction of Zn²⁺ into CdTe NCs widens the Fermi level offset from 0.68 to 0.74 eV, lengthens the depletion region from 130 to 137 nm, and hence brings obvious improvement in the open circuit voltage (V_oc) and fill factor. Especially, the depletion region is successfully tuned from 137 to 171 nm, and even lengthened to a record thickness of 200 nm based on aqueous‐processed solar cells. As a result, a champion thickness ratio (74%) of depletion region to active layer (200/270 nm) is achieved. A champion PCE of 5.96% and short‐circuit current (J_sc) of 21.2 mA cm⁻² are achieved among aqueous‐processed NC solar cells. This work provides a simple way to prepare polynary NCs and highlights a prospective method to develop more efficient and cost‐effective solution‐processed environment friendly solar cells.

中文翻译：

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操纵费米能级偏移扩大的水处理纳米晶体太阳能电池的耗尽区

水溶性纳米晶体（NCs）由于其高消光系数，低成本和良好的光电特性，在水处理太阳能电池中是很有前途的材料。但是，目前水处理的NC太阳能电池的功率转换效率（PCE）受有源层的短耗尽区和NC与电子传输层之间有限的费米能级偏移的限制。在这里，这些问题可以通过制备用2-氨基乙硫醇盐酸盐封端的Cd _x Zn _{1– x} Te NCs有效地解决。将Zn ²⁺引入CdTe NCs中可将费米能级偏移从0.68扩展到0.74 eV，将耗尽区从130 nm扩展到137 nm，从而显着改善开路电压（V _oc）和填充系数。尤其是，基于水处理的太阳能电池，耗尽区已成功地从137 nm调整到171 nm，甚至被延长到200 nm的创纪录厚度。结果，实现了耗尽区与有源层（200 / 270nm）的冠军厚度比（74％）。在经过水处理的NC太阳能电池中，PCE的最佳PCE为5.96％，短路电流（J _sc）为21.2 mA cm ^-2。这项工作为制备多元NC提供了一种简单的方法，并着重介绍了开发更有效，成本效益更高，解决方案处理的环境友好型太阳能电池的前瞻性方法。