Polymer PVP Additive for Improving Stability of Perovskite Solar Cells

doi:10.15541/jim20180172

Abstract

Abstract:

As a type of novel thin film solar cells, perovskite solar cells develope sharply within a decade, which efficiency has approached to that of the commercial silicon solar cells. However, its poor stability in the air has limited the further practical application. Herein, we achieve uniform sable perovskite films under open environment by adding some poly 4-vinylpyridine (PVP). The morphology, structure and performance test results show that the perovskite films added with PVP were more compact and uniform than the bare one. Moreover, the assembled solar cell with 0.4wt% PVP exhibited highly reproducible efficiencies up to 13.07%, much higher than that of 6.09% for the controlled one. When restored in the air with approximately 50% relative humidity in the absence of encapsulation, its efficiency decay time to a half from 3 d for bare one extended to 3 w. However, high PVP additives result in incomplete reaction between PbI₂ and CH₃NH₃I. If the above mentioned process is further optimized, is expected to be applied to the large-scale preparation of more stable perovskite film.

Key words: perovskite solar cell, stability, poly 4-vinylpyridine, polymer additive

CLC Number:

TQ174

XIONG Hao, ZHANG Bo-Xin, JIA Wei, ZHANG Qing-Hong, XIE Hua-Qing. Polymer PVP Additive for Improving Stability of Perovskite Solar Cells[J]. Journal of Inorganic Materials, 2019, 34(1): 96-102.

Figures/Tables 10

Fig. 1 Surface SEM images of PbI2 films on the glass with or without polymer modification (a) Without PVP; (b) 0.2wt% PVP; (c) 0.4wt% PVP; (d) 0.6wt% PVP; (e) 0.8wt% PVP

Fig. 2 Surface SEM images of perovskite films with various concentration of PVP (a) Without PVP; (b) 0.2wt% PVP; (c) 0.4wt% PVP; (d) 0.6wt% PVP; (e) 0.8wt% PVP

Fig. 3 UV-visible absorption spectra of films in presence of varying concentration of PVP (a) PbI2 films; (b) CH3NH3PbI3 films

Fig. 4 Steady state photoluminescence (PL) spectra of perovskite films doped with various concentration of PVP on the glass

Fig. 5 XRD patterns of fresh perovskite films doped with PVP of various quantities; The optical photos from bottom to top in the inserted are 0, 0.2wt%, 0.4wt%, 0.6wt%, 0.8wt% PVP (PbI2 on the left, perovskite on the right)

Fig. 6 XRD patterns of CH3NH3PbI3 doped with PVP of various quantities after three weeks in the air; The optical photos from bottom to top in the inserted are 0, 0.2wt%, 0.4wt%, 0.6wt%, 0.8wt% PVP, respectively (PbI2 on the left, perovskite on the right)

Fig. 7 Photocurrent density-voltage (J-V) curves of the PSCs doped with various concentration of PVP

Table 1 The parameters of as-prepared perovskite solar cells doped with various concentration of PVP

Sample	V_oc/V	J_sc/(mA·cm^-2)	FF/%	PCE/%
Without PVP	0.95	16.17	39.40	6.09
0.2wt% PVP	1.00	19.14	46.10	8.86
0.4wt% PVP	1.04	19.60	64.00	13.07
0.6wt% PVP	1.05	17.39	67.77	12.34
0.8wt% PVP	1.04	14.83	67.38	10.42

Table 2 The parameters of perovskite solar cells doped with various concentration of PVP after three days in the air

Sample	V_oc/V	J_sc/(mA·cm^-2)	FF/%	PCE/%
Without PVP	1.09	12.05	31.64	4.17
0.2wt% PVP	0.78	16.75	48.36	6.33
0.4wt% PVP	1.04	21.05	53.05	11.60
0.6wt% PVP	0.99	21.44	47.12	10.02
0.8wt% PVP	0.84	17.20	66.10	9.52

Table 3 The parameters of perovskite solar cells doped with various concentration of PVP after three weeks in the air

Sample	V_oc/V	J_sc/(mA·cm^-2)	FF/%	PCE/%
Without PVP	0.95	6.18	26.35	1.55
0.2wt% PVP	1.03	15.53	29.75	4.75
0.4wt% PVP	0.80	15.12	54.84	6.63
0.6wt% PVP	0.82	10.88	68.36	6.11
0.8wt% PVP	0.97	21.13	34.29	7.04

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