Park Jong Hyun, Noh Young Wook, Ha Jung Min, Harit Amit Kumar, Tripathi Ayushi, Lee Jeongjae, Lee Bo Ram, Song Myoung Hoon, Woo Han Young
School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan 44919, Republic of Korea.
School of Chemical Engineering, Chonnam National University, Gwangju 61186, Republic of Korea.
ACS Appl Mater Interfaces. 2023 Nov 20. doi: 10.1021/acsami.3c12878.
Perovskite defects are a major hurdle in the efficiency and stability of perovskite solar cells (PSCs). While various defect passivation materials have been explored, most are insulators that hinder charge transport. This study investigates the potential of two different π-conjugated polyelectrolytes (CPEs), MPS2-TEA and PCPDTBT2-TMA, as semiconducting additives in PSCs. The CPEs differ in electrical conductivity, offering a unique approach to bridge defect mitigation and charge carrier transport. Unlike previous uses of CPEs mainly as interlayers or charge transport layers, we explore their direct effect on defect passivation within a perovskite layer. Secondary ion microscopy reveals the even distribution of CPEs within the perovskite layer and their efficient defect passivation potential is studied through various spectroscopic analyses. Comparing MPS2-TEA and PCPDTBT2-TMA, we find MPS2-TEA to be superior in defect passivation. The highly conductive nature of PCPDTBT2-TMA due to self-doping diminishes its defect passivation ability. The negative sulfonate groups in the side chains of PCPDTBT2-TMA stabilize polarons, reducing defect passivation capability. Finally, the PSCs with MPS2-TEA achieve remarkable power conversion efficiencies (PCEs) of 22.7% for 0.135 cm and 20.0% for large-area (1 cm) cells. Furthermore, the device with MPS2-TEA maintained over 87.3% of initial PCE after 960 h at continuous 1-sun illumination and 89% of PCE after 850 h at 85 °C in a nitrogen glovebox without encapsulation. This highlights CPEs as promising defect passivation additives, unlocking potential for improved efficiency and stability not only in PSCs but also in wider applications.
钙钛矿缺陷是钙钛矿太阳能电池（PSC）效率和稳定性的主要障碍。虽然已经探索了各种缺陷钝化材料，但大多数是阻碍电荷传输的绝缘体。本研究调查了两种不同的π共轭聚电解质（CPE），即MPS2-TEA和PCPDTBT2-TMA，作为PSC中半导体添加剂的潜力。这两种CPE的电导率不同，为缓解缺陷和电荷载流子传输提供了一种独特的方法。与之前主要将CPE用作中间层或电荷传输层不同，我们探索了它们对钙钛矿层内缺陷钝化的直接影响。二次离子显微镜揭示了CPE在钙钛矿层内的均匀分布，并通过各种光谱分析研究了它们有效的缺陷钝化潜力。比较MPS2-TEA和PCPDTBT2-TMA，我们发现MPS2-TEA在缺陷钝化方面更具优势。PCPDTBT2-TMA由于自掺杂具有高导电性，这降低了其缺陷钝化能力。PCPDTBT2-TMA侧链中的负磺酸基团使极化子稳定，降低了缺陷钝化能力。最后，含有MPS2-TEA的PSC在0.135平方厘米的电池上实现了22.7%的显著功率转换效率（PCE），在大面积（1平方厘米）电池上实现了20.0%的PCE。此外，含有MPS2-TEA的器件在连续1个太阳光照960小时后保持了初始PCE的87.3%以上，在氮气手套箱中85℃下850小时后保持了89%的PCE，且未进行封装。这突出了CPE作为有前景的缺陷钝化添加剂的地位，不仅为PSC，也为更广泛的应用开启了提高效率和稳定性的潜力。
