Recently perovskite solar cells (PSCs), as photoelectric conversion devices, exhibit excellent power conversion efficiency (PCE) and low-processing cost, and have become one of the most promising devices to replace conventional silicon-based solar cells and address current pressing energy issues. Among them, the flexible PSCs are especially more widely applicable and may propel the rapid advancements of wearable electronics, causing a significant paradigm shift in consumer electronics. Current flexible PSCs use non-biodegradable petroleum-based polymer substrates, discarding of which will aggravate “white pollution”. Therefore, development of green, biodegradable and low-cost flexible substrates will provide a great alternative to flexible PSCs. Here we have developed transparent nanocellulose paper (NCP) with coating of acrylic resin as substrates to fabricate flexible PSCs, which are biodegradable and easily disposable. The PCE of these NCP-based PSCs reached 4.25%, while the power per weight (the ratio of power to device weight) was as high as 0.56 W g^–1. The flexible PSCs also showed good stability, retaining >80% of original efficiency after 50 times of bending. The NCP-based substrates can also be applied to other electronic systems, which may prosper next-generation green flexible electronics.

近年来，钙钛矿型太阳能电池（PSC）作为光电转换设备具有出色的功率转换效率（PCE）和较低的处理成本，并且已成为替代常规硅基太阳能电池并解决当前紧迫的能源问题的最有希望的设备之一。其中，柔性PSC特别适用范围更广，并可能推动可穿戴电子设备的快速发展，从而引起消费电子产品的重大范式转变。当前的柔性PSC使用不可生物降解的石油基聚合物基材，将其丢弃将加剧“白色污染”。因此，开发绿色，可生物降解且低成本的柔性底材将为柔性PSC提供很好的选择。在这里，我们开发了透明的纳米纤维素纸（NCP），其表面涂有丙烯酸树脂作为基材，以制造可生物降解且易于使用的柔性PSC。这些基于NCP的PSC的PCE达到4.25％，而每单位重量的功率（功率与设备重量的比）高达0.56 W g^–1。柔性PSC还显示出良好的稳定性，在弯曲50次后仍能保持> 80％的原始效率。基于NCP的基板也可以应用于其他电子系统，这可能会促进下一代绿色柔性电子产品的发展。