Summarized photovoltaic performance of the ETL-free PSCs.

Year of publication	Structure	PCE (%)	Stability	Stability test parameters	Ref.
2014	ITO glass/MAPbI3/spiro-OMeTAD/Ag	13.5	—	—	137
	ITO glass/MAPbI3/P3HT/Ag
2015	FTO glass/MAPbI3−xClx/spiro-OMeTAD/Au	14.14	>70% of PCE retained	500 h, RH 20%, dark	138
2015	ITO glass/MAPbI3/PBDTTT-C/MoO3/Ag	9.95	—	—	139
2016	FTO glass/MAPbI3:C70/spiro-OMeTAD/Au	13.6	PCE of 7% retained	3 h, continuous light illumination (1 sun)	140
2016	ITO glass/PEDOT:PSS/MAPbI3/Ti/Au	12.91	PCE 70% retained	300 h, ambient environment	141
2017	FTO glass/MAPbI3/spiro-OMeTAD/Au	15.69	No degradation	21 d, ambient air and dark condition	142
2017	FTO glass/MAPbI3/is-2/spiro-OMeTAD/Au	14.3	No significant degradation	124 h, continuous light (AM 1.5, 1 sun)	143
2017	FTO glass/CsFAMA (formamidinium methylammonium)/spiro-OMeTAD/Au	15.42	—	—	144
2018	FTO glass/BCP/CsFAMA/spiro-OMeTAD/Ag	19.07	PCE retained 92.2%	500 h, continuous light (AM 1.5, 1 sun)	145
2018	FTO glass/MAPbI3/spiro-OMeTAD/Au	12.60	PCE dropped by 4.0%	374 h, stored in the ambient environment	146
2018	FTO glass/MAPb1−ySb2y/3I3−xClx/spiro-OMeTAD/Ag	12.62	PCE retained about 70%	148 h, RH 20%, room temperature	147
2019	FTO glass-TMAH/FAMA/spiro-OMeTAD/Au	20.1	PCE retained about 83%	500 h, RH 25%, 30 °C	148
2019	FTO glass/Maze-like MAPbI3/spiro-OMeTAD/Au	18.5	—	—	149
2019	FTO glass/MAPbI3/spiro-OMeTAD/CANPs/Au	18.89	(i) PCE retained about 70%	(i) 25 °C, 35% RH	150
			(ii) PCE retained about 80%	(ii) 540 m, continuous light (AM 1.5, 1 sun)
2020	ITO glass/MAAc/MAPbI3/spiro-OMeTAD/Au	21.08	PCE retained about 86%	400 h, continuous light (AM 1.5, 1 sun)	151
2021	TETA-GR/BCP/MAPbI3:GQDs/PTAA/Au	15.72	PCE retained about 83%	500 h, ambient environment	152
2021	ITO/MSAPBS/(FAPbI3)0.85(MAPbBr3)0.15/spiro-OMeTAD/Au	20.55	—	—	153