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The omnipresent electroluminescence (EL) emitted from the charge transfer states in several different types of polymer solar cells is detected. The correlation of different voltage emission and the lower energy blend of EL are also discussed.

We studied charge carrier recombination in methylammonium lead iodide (MAPbI 3 ) perovskite and the impact of interfaces on the charge carrier lifetime using time-resolved photoluminescence. Pristine films and those covered with organic electron and hole transport materials (ETM and HTM) were investigated at various laser repetition rates ranging from 10 kHz to 10 MHz in order to separate the bulk and interface-affected recombination. We revealed two different components in the PL decay. The fast component (shorter than 300 ns) is assigned to interfacial processes and the slow one to bulk recombination. A high repetition pulse train was shown to shorten PL decay in pristine perovskite while significantly prolonging the photocarrier lifetime in MAPbI 3 covered by TMs. This effect can be qualitatively explained with a kinetic model taking interface traps into account. We demonstrate a significant influence of the excitation repetition rate on photocarrier lifetime, which should be considered when studying charge carrier dynamics in perovskites.

Thermally stimulated current (TSC) measurements are used to characterize electronic trap states in methylammonium lead iodide perovsite solar cells. Several TSC peaks were observed over the temperature range from 20 K to room temperature. To elucidate the origins of these peaks, devices with various organic charge transport layers and devices without transport layers were tested. Two peaks appear at very low temperatures, indicating shallow trap states that are mainly attributed to the PCBM/C60 electron transport bilayer. However, two additional peaks appear at higher temperatures, that is, they are deeper in energy, and are assigned to the perovskite layer. At around T = 163 K, a sharp peak, also present in the dark TSC measurements, is assigned to the orthorhombic-tetragonal phase transition in the perovskite. However, a peak at around T = 191 K is assigned to trap states with activation energies of around 500 meV but with a rather low concentration of 1 × 10(21) m(-3).

Processing and patterning of electroactive materials from solvents is a hallmark of flexible organic electronics, and commercial applications based on these properties are now emerging. Printing and ink-jetting are today preferred technologies for patterning, but these limit the formation of nanodevices, as they give structures way above the micrometer lateral dimension. There is therefore a great need for cheap, large area patterning of nanodevices and methods for top-down registration of these. Here we demonstrate large area patterning of connected micro/nanolines and nanotransistors from the conducting polymer PEDOT, assembled from fluids. We thereby simultaneously solve problems of large area nanopatterning, and nanoregistration.