Shi Yuxin, Gong Yongshuai, Zhang Yang, Li Yunchao, Li Xiaohong, Tan Zhan'ao, Fan Louzhen
Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering Department, Beijing University of Chemical Technology Institution, Beijing, 100029, China.
Adv Sci (Weinh). 2024 Sep;11(35):e2400817. doi: 10.1002/advs.202400817. Epub 2024 Jul 19.
Although power conversion efficiency (PCE) of solar cells (SCs) continues to improve, they are still far from practical application because of their complex synthesis process, high cost and inferior operational stability. Carbon quantum dots with high material stability and remarkable photoluminescence are successfully used in light-emitting diodes. A good light emitter should also be an efficient SC according to the photon balance in Shockley-Quieisser formulation, in which all excitons are ultimately separated. However, the finite quantum-sized sp domain leads to tight exciton bonding, and highly delocalized electron clouds in irregular molecular stacks form disordered charge transfer, resulting in severe energy loss. Herein, an axially growing carbon quantum ribbon (AG-CQR) with a wide optical absorption range of 440-850 nm is reported. Structural and computational studies reveal that AG-CQRs (aspect ratio ≈2:1) with carbonyl groups at both ends regulate energy level and efficiently separate excitons. The stacking-controlled two-dimensional AG-CQR film further directionally transfers electrons and holes, particularly in AB stacking mode. Using this film as active layer alone, the SCs yield a maximum PCE of 1.22%, impressive long-term operational stability of 380 h, and repeatability. This study opens the door for the development of new-generation carbon-nanomaterial-based SCs for practical applications.
尽管太阳能电池（SCs）的功率转换效率（PCE）不断提高，但由于其合成过程复杂、成本高且运行稳定性差，仍远未达到实际应用水平。具有高材料稳定性和显著光致发光特性的碳量子点已成功应用于发光二极管。根据肖克利 - 奎塞尔公式中的光子平衡，一个好的发光体也应该是一个高效的太阳能电池，其中所有激子最终都会分离。然而，有限的量子尺寸sp域会导致激子紧密结合，并且不规则分子堆叠中高度离域的电子云会形成无序的电荷转移，从而导致严重的能量损失。在此，报道了一种轴向生长的碳量子带（AG - CQR），其具有440 - 850 nm的宽光学吸收范围。结构和计算研究表明，两端带有羰基的AG - CQR（长宽比≈2:1）可调节能级并有效分离激子。堆叠控制的二维AG - CQR薄膜进一步定向传输电子和空穴，特别是在AB堆叠模式下。仅使用该薄膜作为活性层，太阳能电池的最大PCE为1.22%，具有令人印象深刻的380小时长期运行稳定性和可重复性。这项研究为开发用于实际应用的新一代基于碳纳米材料的太阳能电池打开了大门。
