In this paper we present a new transient photoconductivity (TPC) inversion method for the determination of the density of localized states (DOS) energy distribution g(E) in thin film semiconductor materials with exact matrix solution for g(E). The method, derived from the multiple trapping model, is based on prior determination of the exact transient trap occupation function and applies to the pre-recombination time range of the TPC. It is demonstrated by application to simulated TPC data that high energy resolution can be achieved for the case of continuous DOS distribution, appropriate to amorphous semiconductors, as well as for discrete level DOS such as in crystalline semiconductors. (C) 2007 Elsevier Ltd. All rights reserved.