Encapsulation and Outdoor Testing of Perovskite Solar Cells: Comparing Industrially Relevant Process with a Simplified Lab Procedure

Abstract

Perovskite solar cells (PSCs) have shown great potential for next-generation photovoltaics. One of the main barriers to their commercial use is their poor long-term stability under ambient conditions and, in particular, their sensitivity to moisture and oxygen. Therefore, several encapsulation strategies are being developed in an attempt to improve the stability of PSCs in a humid environment. The lack of common testing procedures makes the comparison of encapsulation strategies challenging. In this paper, we optimized and investigated two common encapsulation strategies: lamination-based glass–glass encapsulation for outdoor operation and commercial use (COM) and a simple glue-based encapsulation mostly utilized for laboratory research purposes (LAB). We compare both approaches and evaluate their effectiveness to impede humidity ingress under three different testing conditions: on-shelf storage at 21 °C and 30% relative humidity (RH) (ISOS-D1), damp heat exposure at 85 °C and 85% RH (ISOS-D3), and outdoor operational stability continuously monitoring device performance for 10 months under maximum power point tracking on a roof-top test site in Berlin, Germany (ISOS-O3). LAB encapsulation of perovskite devices consists of glue and a cover glass and can be performed at ambient temperature, in an inert environment without the need for complex equipment. This glue-based encapsulation procedure allowed PSCs to retain more than 93% of their conversion efficiency after 1566 h of storage in ambient atmosphere and, therefore, is sufficient and suitable as an interim encapsulation for cell transport or short-term experiments outside an inert atmosphere. However, this simple encapsulation does not pass the IEC 61215 damp heat test and hence results in a high probability of fast degradation of the cells under outdoor conditions. The COM encapsulation procedure requires the use of a vacuum laminator and the cells to be able to withstand a short period of air exposure and at least 20 min at elevated temperatures (in our case, 150 °C). This encapsulation method enabled the cells to pass the IEC 61215 damp heat test and even to retain over 95% of their initial efficiency after 1566 h in a damp heat chamber. Above all, passing the damp heat test for COM-encapsulated devices translates to devices fully retaining their initial efficiency for the full duration of the outdoor test (>10 months). To the best of the authors’ knowledge, this is one of the longest outdoor stability demonstrations for PSCs published to date. We stress that both encapsulation approaches described in this work are useful for the scientific community as they fulfill different purposes: the COM for the realization of prototypes for long-term real-condition validation and, ultimately, commercialization of perovskite solar cells and the LAB procedure to enable testing and carrying out experiments on perovskite solar cells under noninert conditions.

Perovskite Solar Module Outdoor Field Testing and Spectral Irradiance Effects on Power Generation

“…These results further demonstrate that the outdoor spectral red shift in the morning and evening hours contributes to the PV enhancement of the PSC system, because it increases the ratio of available energy. Similar PR changes have also been reported in literature on the outdoor stability of PSCs, [ 21 ] but no in‐depth research has been carried out on this point. In addition, interestingly, although the irradiance and ER are basically close, the PR of the PSC in the evening is significantly higher than in the morning.…”

Recent Advances in the Combined Elevated Temperature, Humidity, and Light Stability of Perovskite Solar Cells

“…[ 77 ] Emery et al compared the “LAB” encapsulation method using UV‐glue with “COM” using POE hot press and butyl rubber edge sealing, which showed the “COM” encapsulation scheme can pass the IEC 61215 damp heat test. [ 182 ]…”

“…[77] Emery et al compared the "LAB" encapsulation method using UV-glue with "COM" using POE hot press and butyl rubber edge sealing, which showed the "COM" encapsulation scheme can pass the IEC 61215 damp heat test. [182] Through the analysis of these successful 85% RH/85 °C aging test cases, it can be found that several aspects play a crucial role in passing the damp heat aging test. First, a stable perovskite component containing FA, Cs was proposed.…”

Efficient and Thermally Stable All‐Perovskite Tandem Solar Cells Using All‐FA Narrow‐Bandgap Perovskite and Metal‐oxide‐based Tunnel Junction

“…Although encapsulation can effectively protect the devices from moisture and oxygen, it cannot completely tackle the challenge of thermal‐induced degradation. [ 8,9 ] Further research is, therefore, urgently needed to improve the instinct thermal stability of all‐perovskite tandem solar cells.…”

“…Although encapsulation can effectively protect the devices from moisture and oxygen, it cannot completely tackle the challenge of thermal-induced degradation. [8,9] Further research is, therefore, urgently needed to improve the instinct thermal stability of all-perovskite tandem solar cells.The thermal stability and performance of mixed Pb-Sn PSCs can be influenced by manipulating the composition of the perovskite, especially the A-site cation. [10][11][12][13] Currently, the efficient mixed Pb-Sn narrow-bandgap (NBG) PSCs are primarily achieved by the incorporation of MA cation (>30%).…”