Park Jong-Jin, Heo Youn-Jung, Yun Jin-Mun, Kim Yunseul, Yoon Sung Cheol, Lee Seung-Hoon, Kim Dong-Yu
Heeger Center for Advanced Materials (HCAM), School of Materials Science and Engineering (SMSE), Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
Research Institute of Sustainable Manufacturing Systems, Korea Institute of Industrial Technology (KITECH), Cheonan 31056, Republic of Korea.
ACS Appl Mater Interfaces. 2020 Sep 23;12(38):42811-42820. doi: 10.1021/acsami.0c11384. Epub 2020 Aug 31.
Creating an orthogonal printable hole-transporting layer (HTL) without damaging the underlying layer is still a major challenge in fabricating large-area printed inverted polymer solar cells (PSCs). In this study, we prepared orthogonal-processable fluorine-functionalized reduced graphene oxide (FrGO) series with various two-dimensional sheet sizes such as large-sized FrGO (1.1 μm), medium-sized FrGO (0.7 μm), and small-sized FrGO (0.3 μm) and systematically investigated the size effect of FrGOs on the hole transport properties of PSCs. The FrGOs exhibit highly stable dispersion without change over 90 days in 2-propanol solvent, indicating very high dispersion stability. Decreasing the sheet size of FrGOs enhanced hole-transporting properties, resulting in power conversion efficiencies (PCEs) of 9.27 and 9.02% for PTB7-Th:EH-IDTBR- and PTB7-Th:PCBM-based PSCs, respectively. Compared to devices with solution-processed poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), a 14% enhancement of PCEs was achieved. Interestingly, the PCEs of devices with the smallest FrGO sheet are higher than the PCE of 8.77% of a device with vacuum-deposited MoO. The enhancement in the performance of PSCs is attributed to the enhanced charge collection efficiency, decreased leakage current, internal resistance, and minimized charge recombination. Finally, small-sized FrGO HTLs were successfully coated on the photoactive layer using the spray coating method, and they also exhibited PCEs of 9.22 and 13.26% for PTB7-Th:EH-IDTBR- and PM6:Y6-based inverted PSCs, respectively.
在制造大面积印刷倒置聚合物太阳能电池（PSC）时，创建一个不会损坏底层的正交可印刷空穴传输层（HTL）仍然是一个重大挑战。在本研究中，我们制备了具有不同二维片层尺寸的正交可加工氟功能化还原氧化石墨烯（FrGO）系列，如大尺寸FrGO（1.1μm）、中尺寸FrGO（0.7μm）和小尺寸FrGO（0.3μm），并系统研究了FrGO尺寸对PSC空穴传输性能的影响。FrGO在异丙醇溶剂中表现出高度稳定的分散性，90天内无变化，表明其具有非常高的分散稳定性。减小FrGO的片层尺寸可增强空穴传输性能，基于PTB7-Th:EH-IDTBR和PTB7-Th:PCBM的PSC的功率转换效率（PCE）分别达到9.27%和9.02%。与采用溶液法制备的聚（3,4-乙撑二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS）的器件相比，PCE提高了14%。有趣的是，具有最小FrGO片层的器件的PCE高于采用真空沉积MoO的器件的8.77%的PCE。PSC性能的提高归因于电荷收集效率的提高、漏电流的降低、内阻的降低以及电荷复合的最小化。最后，使用喷涂法成功地在光活性层上涂覆了小尺寸FrGO HTL，基于PTB7-Th:EH-IDTBR和PM6:Y6的倒置PSC的PCE分别为9.22%和13.26%。
