One-step roll-to-roll air processed high efficiency perovskite solar cells

• Published in: Nano energy 2018-04, Vol.46, p.185-192
• Main Authors: Zuo, Chuantian, Vak, Doojin, Angmo, Dechan, Ding, Liming, Gao, Mei
• Format: Article
• Language: English
• Subjects: Drop casting; Flexible; Perovskite solar cells; Roll-to-roll processing; Slot-die coating
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2018.01.037

The rapid improvement in power conversion efficiencies (PCE) to record high levels have highlighted perovskite solar cells’ great potential to be commercialized in the near future. Continuous roll-to-roll (R2R) processing on flexible substrates enables ultra low-cost and high throughput manufacturing, which is essential for perovskite solar cells to make a breakthrough in cost per Watt compared to commercially established solar cells technologies. Here we demonstrate a facile spin-coating-free and R2R compatible blowing-assisted drop-casting (BADC) method to prepare CH3NH3PbI3 films for perovskite solar cells. The crystallinity and morphology of CH3NH3PbI3 films and device performance are significantly improved by optimization of the formulation with an NH4Cl additive. The perovskite solar cell prepared in air with a maximum PCE of 19.48% is obtained using modified poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (m-PEDOT:PSS) as the hole transport layer (HTL). The cells based on the structure of ITO/m-PEDOT:PSS/CH3NH3PbI3/PCBM/Ca/Al exhibit negligible current hysteresis. The optimized formulation is then successfully applied to slot-die coating on glass and subsequently to R2R on a flexible substrate, giving record PCEs of 15.57% and 11.16%, respectively. [Display omitted] •A blowing-assisted drop-casting method was used to prepare CH3NH3PbI3 films in air. The morphology and crystallinity of CH3NH3PbI3 films were improved significantly by using NH4Cl additive.•Planar p-i-n perovskite solar cell with a PCE of 19.48% was achieved using modified PEDOT:PSS as the hole transport layer.•Cells with PCEs of 15.57% and 11.16% were obtained by using the slot-die coating and the R2R process, respectively.