Carbon Convergence Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, 92 Chudong-Ro, Bongdong-eup, Wanju-gun, Jeonbuk 55324, Republic of Korea.
Nanoscale. 2019 Jan 17;11(3):890-900. doi: 10.1039/c8nr05698f.
Solution-processable graphenes (represented by reduced graphene oxides, rGOs) have shown promising abilities as HTLs in perovskite solar cells (PeSCs). However, there has been no attempt to systematically tailor the characteristics of rGOs to the specifications of PeSCs. Furthermore, the applications of rGO HTLs have been limited to the spin-coating system, which is incompatible with roll-to-roll manufacturing. Here, with the aid of a polymer-graphene hybrid structure and a controllable synthesis method, we successfully developed a much more feasible rGO HTL and demonstrated highly efficient, stable, and printable p-i-n planar PeSCs with facile one-step processing. The characteristics of the developed polyacrylonitrile-grafted rGOs (PRGOs) were optimized by varying the synthesis conditions including the γ-radiation intensity (200, 400, and 600 kGy) and the concentration of the acrylonitrile (AN) precursor (2, 4, and 6 wt%). It is revealed that the PRGO synthesized with a lower AN concentration and a higher irradiation intensity (PRGO_2-600) is the most suitable one for PeSC HTL. PRGO_2-600 effectively raises the average power conversion efficiencies (PCEs) of PeSCs by ∼36% compared to those of conventional PeSCs using PEDOT:PSS HTL. The comprehensive investigations confirm that the enhanced device efficiency stems from (1) the favorable interlayer characteristics of the PRGO itself and (2) the well-crystallized perovskite layer grown on the PRGO. In addition to the PCE, thechemically inert PRGOs can also maintain their electrical properties over time and retard the decomposition of perovskite films, thereby prolonging the operation time of PeSCs in the atmosphere. More importantly, the applicability of the PRGO HTL is clearly verified even in the roll-to-roll compatible slot-die coating system, exhibiting comparable performances to those of the spin-coating system.
可溶液加工的石墨烯（以还原氧化石墨烯，rGO 为例）已显示出作为钙钛矿太阳能电池（PeSCs）空穴传输层（HTLs）的有前途的能力。然而，还没有人试图系统地根据 PeSCs 的规格来调整 rGO 的特性。此外，rGO HTLs 的应用仅限于旋涂系统，而旋涂系统与卷对卷制造不兼容。在这里，借助聚合物-石墨烯杂化结构和可控合成方法，我们成功地开发了一种更可行的 rGO HTL，并通过简便的一步处理，展示了高效、稳定且可打印的 p-i-n 平面 PeSCs。通过改变合成条件，包括γ辐射强度（200、400 和 600 kGy）和丙烯腈（AN）前体浓度（2、4 和 6 wt%），优化了接枝聚丙烯腈的 rGOs（PRGOs）的特性。结果表明，在较低的 AN 浓度和较高的辐射强度（PRGO_2-600）下合成的 PRGO 最适合用作 PeSC HTL。与使用 PEDOT:PSS HTL 的传统 PeSCs 相比，PRGO_2-600 可将 PeSCs 的平均功率转换效率（PCE）提高约 36%。综合研究证实，器件效率的提高源于（1）PRGO 本身的有利层间特性，以及（2）在 PRGO 上生长的结晶良好的钙钛矿层。除了 PCE 之外，化学惰性的 PRGOs 还可以随着时间的推移保持其电性能，并延缓钙钛矿薄膜的分解，从而延长 PeSCs 在大气中的运行时间。更重要的是，即使在与卷对卷兼容的狭缝模涂层系统中，PRGO HTL 的适用性也得到了明显验证，其性能与旋涂系统相当。
