Publication
The invention relates to a dopant-free perovskite optoelectronic or photovoltaic device presenting molecular orbital stretching-junction, wherein the hole transport layer is a multilayer structure comprising at least two layers, each layer comprising a different hole transport material (HTM) having a different ionization energy (IP) for each layer and selected from donor material or acceptor material. The sequence of the layers in the multilayer structure of the hole transport layer is configured such that the layer of the hole transport layer in direct contact with the light-harvesting layer (4) is a layer comprising a donor material with an IP value being ≤-5.00 eV and ≥-5,60 eV, which is equal to or higher than the IP value of the organic/inorganic metal halide perovskite, the IP value of each HTM being lower than the work function of a material of the back contact or the counter electrode.