“Perovskite / Carbon” interface has remained a key bottleneck for the hole‐conductor‐free perovskite solar cells based on carbon‐electrode (CPSCs), due to problems like loose physics contact, defects, energy mismatch, poor chemical coupling, etc. A previous study shows that octylammonium iodide (OAI) blending in carbon paste induced a kind of “in‐situ healing” effect for “perovskite / carbon” interface, and improved power conversion efficiency from ≈13% to >19%. Here the beneath mechanism is further explored by careful examination of the interaction between OAI molecule and carbon black (CB) nanoparticles. It comes to show that, the famous “CB adsorption” plays a key role during the “healing” processes. Due to CB adsorption behavior, the mass ratio between OAI and CB influences much on the healing effect. By suitably adjusting the mass ratio between OAI and CB, and increasing the light harvest of perovskite, an efficiency of 19.41% is achieved for the hole‐conductor‐free CPSCs. Device efficiency and the charge‐extraction and recombination process are tracked with the storage period, continuous improvement appears for devices assembled by relatively higher CB mass. A kind of “slow‐release effect” is revealed during the OAI‐induced “in‐situ healing” process, which is caused by the famous “CB adsorption” behavior.

中文翻译：

---

碘化辛铵诱导的钙钛矿/碳界面原位修复行为：炭黑吸附引起的“缓释效应”

由于物理接触松散、缺陷、能量失配、化学耦合不良等问题，“钙钛矿/碳”界面仍然是基于碳电极（CPSC）的无空穴导体钙钛矿太阳能电池的关键瓶颈。先前的研究表明，在碳糊中掺入碘化辛铵（OAI）可以引起“钙钛矿/碳”界面的“原位修复”效应，并将功率转换效率从约13%提高到>19%。在这里，通过仔细检查 OAI 分子和炭黑 (CB) 纳米粒子之间的相互作用，进一步探讨了下面的机制。事实证明，著名的“CB吸附”在“治愈”过程中发挥着关键作用。由于CB的吸附行为，OAI和CB之间的质量比对愈合效果影响很大。通过适当调整OAI和CB之间的质量比，并增加钙钛矿的光捕获，无空穴导体CPSC的效率达到19.41%。器件效率以及电荷提取和复合过程随着存储时间的推移而变化，由相对较高的CB质量组装的器件出现了持续改进。在OAI诱导的“原位愈合”过程中揭示了一种“缓释效应”，这是由著名的“CB吸附”行为引起的。