Potassium iodide reduces the stability of triple-cation perovskite solar cells

Abstract

The addition of alkali metal halides to hybrid perovskite materials can significantly impact their crystallisation and hence their performance when used in solar cell devices.

Optimization of SnO2 electron transport layer for efficient planar perovskite solar cells with very low hysteresis

“…We note that the s-PCE in case of c-NP-SnO 2 and c(Li)-NP-SnO 2 is slightly lower than both the reverse and forward scan PCE. We speculate that this is related to a reduction in charge carrier extraction during the first seconds of device operation, as recently reported by Thiesbrummel et al 66 We also fabricated PSCs with a single SnO 2 NP layer (NP-SnO 2 ) as it is a well-established ETL in the literature [15][16][17][18]31,55,63,67,68 and our laboratory. [69][70][71] The champion PSC with NP-SnO 2 ETL shows a reverse scan PCE and s-PCE of 19.3% and 16.3% respectively (Fig.…”

“…The PSCs with c-NP-SnO 2 ETL show a slightly lower average PCE of 18.3%, however, the HI is reduced to 0.06, which is attributed to the presence of K ions at the surface of the NP-SnO 2 layer (as will be verified later) that results in passivation of halide vacancies at the ETL/ perovskite interface, in line with previous reports. 55,63 PSCs with c(Li)-SnO 2 ETL show the highest short-circuit current density ( J SC ) and lowest open-circuit voltage (V OC ) among all ETLs, respectively, 65 however, the HI is strongly increased to 0.53. In contrast, PSCs with c(Li)-NP-SnO 2 ETL exhibit the combined benefits of Li and K with significant improvements in J SC as well as FF as compared to PSCs with c-SnO 2 ETL, leading to an average PCE of 19.3% with by far the lowest HI of 0.03 among all studied ETLs.…”

“…Many approaches have been proposed in this regard: (i) a bilayer ETL structure composed of two metal oxide films; [31][32][33][34][35] (ii) doping of the ETL; 5,18,19,36-40 (iii) an interfacial modification at the ETL/ perovskite interface; 30,32,[41][42][43][44][45][46][47][48][49][50][51][52] or (iv) doping the perovskite bulk. [53][54][55][56] Lithium (Li) has been introduced as promising dopant 5,36,[57][58][59][60][61] for improving the ETL/perovskite interface among others. [37][38][39][40] In case of mesoporous TiO 2 , it has been shown that a post-treatment with Lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) as the Li source can improve the electronic properties of TiO 2 , resulting in an enhanced electron mobility and a reduced electron trap density in TiO 2 .…”

“…63,64 The KBr-rich interface could passivate halide vacancies at the interface, resulting in high performance and hysteresis-free PSCs when employing this commercial product to form the SnO 2 ETL. [54][55][56]63 Here, we study if the advantages of both Li and K can be exploited by introducing a bilayer ETL composed of Li-doped compact SnO 2 (c(Li)-SnO 2 ) and K-capped SnO 2 NPs (NP-SnO 2 ) layers, i.e. c(Li)-NP-SnO 2 .…”

A sensitive voltammetric sensor for specific recognition of vitamin C in human plasma based on MAPbI3 perovskite nanorods

“…Moreover, as shown in Fig. 1, the XRD pattern of the MAPbI3 presents all characteristic peaks of MAPbI3 with good tetragonal structures with good crystallinity [25,26]. Electrochemical characterization of the L-cys@MAPbI3/GCE:…”