A series of layer-by-layer (LbL) ternary organic photovoltaics (OPVs) were prepared with polymer PM1 as a donor, small molecule L8-BO as an acceptor, and a highly crystalline small molecule D18A as the third component. The power conversion efficiency (PCE) of LbL OPVs can be increased from 18.31% to 19.25% by incorporating 30 wt% D18A into the PM1 layer, resulting from the synergistically increased short circuit current density (J_SC) of 27.02 mA cm⁻², open circuit voltage (V_OC) of 0.909 V, and fill factor (FF) of 78.38%. The main contributions of the appropriate D18A on performance improvement can be summarized as follows: (i) serving as the energy donor to transfer its energy to L8-BO for improving exciton utilization, leading to J_SC improvement of ternary LbL OPVs; (ii) acting as a nucleating agent to induce a more ordered molecular arrangement of PM1 for more effective charge transport, resulting in an FF increment of ternary LbL OPVs; (iii) reducing the non-radiative recombination loss for the increased V_OC of ternary LbL OPVs. This work indicates that introducing highly crystalline small molecule material should be an effective method to synergistically optimize the donor and acceptor layers for achieving highly efficient LbL OPVs.

中文翻译：

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通过高度结晶材料作为能量供体和成核剂，实现超过 19.2% 的逐层有机光伏效率


以聚合物PM1为供体、小分子L8-BO为受体、高结晶小分子D18A为第三组分，制备了一系列层层式（LbL）三元有机光伏（OPV）。通过将 30 wt% D18A 纳入 PM1 层，LbL OPV 的功率转换效率 (PCE) 可从 18.31% 提高到 19.25%，这是由于协同增加的短路电流密度 (J _SC ) 27.02 mA cm ⁻² ，开路电压 (V _OC ) 为 0.909 V，填充因子 (FF) 为 78.38%。适当的D18A对性能改进的主要贡献可以概括如下：（i）作为能量供体将其能量转移到L8-BO以提高激子利用率，从而导致三元的J _SC 改进LbL OPV； (ii) 充当成核剂，诱导 PM1 分子排列更加有序，从而实现更有效的电荷传输，从而导致三元 LbL OPV 的 FF 增加； (iii) 减少三元 LbL OPV 增加的 V _OC 的非辐射复合损失。这项工作表明，引入高结晶小分子材料应该是协同优化供体层和受体层以实现高效 LbL OPV 的有效方法。