Perovskite solar cells: novel modeling approaches for invertible current–voltage characteristics

This paper discusses the invertible current–voltage characteristics of perovskite solar cells (PSCs). To that end, the well-known invertible analytical current–voltage dependencies expressed through the Lambert W function are analyzed and checked on three examples. It is concluded that the expression for voltage–current characteristics is not applicable for a whole voltage range (for no-load and low-load operation). Therefore, an analytical closed-form expression for PSC voltage–current characteristics is derived by using the g-function (or LogWright function). Second, a novel closed-form expression for the no-load voltage is derived. Third, a novel iterative procedure for solving the g-function is proposed. The proposed iterative procedure for solving g-functions, called g-IP, is independent of the initial conditions, unlike in the literature. Furthermore, for large values of the argument of the g-function, approximate solutions for g-function solving were derived and tested, especially for regions about the maximum power point. The proposed approach guarantees an accurate representation of the PSC voltage–current characteristics. Therefore, this paper represents unique research in the field of PSC modeling.