Triple-junction perovskite–perovskite–silicon solar cells with power conversion efficiency of 24.4%

The recent tremendous progress in monolithic perovskite-based double-junction solar cells is just the start of a new era of ultra-high-efficiency multi-junction photovoltaics. We report on triple-junction perovskite–perovskite–silicon solar cells with a record power conversion efficiency of 24.4%. Optimizing the light management of each perovskite sub-cell (∼1.84 and ∼1.52 eV for top and middle cells, respectively), we maximize the current generation up to 11.6 mA cm−2. Key to this achievement was our development of a high-performance middle perovskite sub-cell, employing a stable pure-α-phase high-quality formamidinium lead iodide perovskite thin film (free of wrinkles, cracks, and pinholes). This enables a high open-circuit voltage of 2.84 V in a triple junction. Non-encapsulated triple-junction devices retain up to 96.6% of their initial efficiency if stored in the dark at 85 °C for 1081 h.

) 15.9 0.55 2.65 10.9 BS 15.2 0.53 2.62 10.9 FS Fig. S13 EQE spectra for the MTJSCs.The WBG was fabricated by AS method with a variation of perovskite precursor concentration of 0.8 or 1.0 M. The MBG was fabricated by VAG method with a variation of perovskite precursor concentration of 1.3 or 1.5 M. TCO deposition was applied to recipe 2: 165 nm IZO with a high deposition pressure of 1.5 mTorr and a low power supply of 100 W.

Fig. S1
Fig. S1 Heatmap of simulated PCEs of perovskite-perovskite-Si MTJSCs for varied bandgap combinations of top and middle perovskites.

Fig. S2
Fig. S2 Simulated data of PCE and JSC of perovskite-perovskite-Si MTJSCs for varied bandgap combinations of top and middle perovskites.The thickness of top perovskite is fixed to 200 nm.

Fig. S10
Fig. S10 EQE and reflectance spectra for the MTJSC combined with perovskite bandgaps of 1.84 eV and 1.52 eV.(a) Using different TCO layers (recipe 1: 90 nm IZO with a low deposition pressure of 0.8 mTorr and a high power supply of 200 W; recipe 2:165 nm IZO with a high deposition pressure of 1.5 mTorr and a low power supply of 100 W; 120 nm IOH).(b) EQE spectra of the champion MTJSC without MgF2 antireflection coating.(c) Comparison of reflectance for the champion MTJSC with and without MgF2 antireflection coating.
Fig. S14 Statistical distribution of the photovoltaic parameters for semitransparent single-junction top perovskite solar cells.(a) PCE, (b) FF, (c) VOC, and (d) JSC.The WBG thin films were fabricated by VAG or AS methods with a perovskite precursor concentration of 0.8 M.
Fig. S19 Normalized intensity of XRD patterns for FAPbI3 thin films (fabricated by VAG and AS methods) and sequential deposition of C60 and SnOx layers.
Fig. S20 Characteristics of non-radiative recombination for semitransparent middle sub-cell.(a) SCLC analyses, (b) dark J-V characteristics, (c) Mott-Schottky plots, and (d) Nyquist plots.The inset in (d) is the equivalent circuit diagram.In the low-frequency region of (d), the straight-like transmission line is related to neglected charge carrier diffusion, which is not considered for fitting.1

Table S2
Summary of different parameters for EIS measurements for FAPbI3-based semitransparent single-junction solar cells.Rs: series resistance; Rrec: charge recombination resistance; Crec: charge recombination capacitance.All data were fitted by Z-View.