Two-dimensional layered organic-inorganic perovskite hybrids have attracted increasing attention due to their outstanding moisture resistance and promising optoelectronic properties. However, the photovoltaic performance in solar cells is still a huge challenge for two-dimensional perovskite films. With the aim to improve the efficiency of 2D perovskite solar cells, the new (ClC6H4C2H4NH3)(2)MA(n - 1)Pb(n)I(3n + 1) perovskite family (abbreviated as (CPEA)(2)MA(n - 1)Pb(n)I(3n) (+) (1)) are synthesized by a simple one-step hot-casting method in this study. It is found that the variation of n value (n = 3-6) has great influence on the microstructure, grain size, charge mobility, trap density and photovoltaic performance of the 2D (CPEA)(2)MA(n - 1)Pb(n)I(3n) (+) (1). Due to the best film quality and prolonged carrier lifetime, the (CPEA)(2)MA(4)Pb(5)I(16) (n = 5) perovskite solar cell exhibits a highest efficiency of 11.86%, with a V-oc of 0.989 V, a J(sc) of 19.92 mA/cm(2) and FF of 60%, respectively. It is anticipated that our approach to explore new organic spacer cations in 2D perovskites may pave the way for their application with high performance.