Fig. 3: Nanoindentation test results of the BHJ films.
From: Multi-scale mechanical properties of bulk-heterojunction films in polymer solar cells
a The schematic diagram of the nanoindentation test together with a typical load versus displacement (P − h) curve. b The representative P − h curves of active layer films based on different electron acceptors. The modulus distributions of c PM6:PC71BM, d PM6:Y6, and e PM6:PRi-C39 films. The hardness distributions of f PM6:PC71BM, g PM6:Y6, and h PM6:PRi-C39 films. i The extracted statistical values of he, hp, and hc from the P − h curves. Data are presented as mean ± SD. j Changes of indentation displacement with time during holding.
