Research Blogs
Quantification of trap states by thermally stimulated current in thin film solar cells
The performance of light-emitting (LEDs) and photovoltaic (PV) devices depends on the quality of the photoactive semiconductor material. The unintentional introduction of defects in the semiconductor material due to material impurities or during the fabrication process causes the deviation from optimal performance.
These defects are referred to as trap states, or in short “traps”, which are energetic states within the bandgap of a semiconductor. In general, traps can occur due to material impurities (in the bulk) or at the interfaces between layers of different materials.
In the following blog post, we will present how to characterize the trap states with the technique called thermally stimulated current (TSC). We also propose a method to reliably interpret the TSC results based on drift-diffusion simulations.
How ISOS Protocols Are Used to Assess Perovskite Solar Cell Stability
How can we assess the long-term stability of perovskite solar cells (PSCs)?
This guide summarizes the latest community-driven recommendations for perovskite stability testing—built upon the ISOS protocols originally developed for organic photovoltaics. It outlines tailored aging experiments, explains key ISOS categories (D, L, O, T, LT, etc.), and explores how tools like Litos Lite help ensure reproducible, standard-compliant stability measurements.
How to quantify Non-radiative voltage losses and recombination in solar cells
The open-circuit voltage (Voc) is the electrical potential difference between the two terminals of a solar cell, when there is no external load applied, hence no electric current flows. Correspondingly, this means that, when a voltage equivalent to the Voc is applied to the terminals of the solar cell, the recombination current (Jrec, which typically follows a non-ideal diode equation) and the photocurrent (Jph, the current generated by illuminating the solar cell) are equal, hence the net current is zero (Jrec=Jph at V= Voc).
Solar cells often present also non-radiative recombination mechanisms, in addition to the radiative one, as a result of poor material quality and non-idealities. To increase the Voc and thus potentially the power conversion efficiency, it is necessary to minimize the ΔVoc,nrad. It is, therefore, necessary to quantify the total loss and determine its origin.
Electroluminescence (EL) and photoluminescence quantum yield (PLQY) allow to directly extract the ΔVoc,nrad for thin-film solar cells such as perovskite solar cells, kesterite, perovskite, organic, or quantum dot. solar cells.
After quantifying the losses, the combination of capacitance-voltage (CV), temperature-dependent voltage characteristics (JV-T), and capacitance-frequency (Cf-T) measurements are essential to identify the recombination mechanisms.
Why Perovskite Solar cells with High Efficiency Show Small iV-curve Hysteresis
In many perovskite solar cells, hysteresis is observed between the forward and reverse current-voltage (IV) scans. This IV curve hysteresis can be problematic for the correct determination of the Power Conversion Efficiency (PCE). While the exact origin of the IV curve hysteresis has remained a topic of debate, it is now widely accepted that mobile ions are the principal cause. However, it is still the subject of ongoing debates about how exactly mobile ions influence the device operation.
In this blog, we are showing how a proper drift-diffusion simulation can help in understanding how mobile ions are affecting the JV characteristics of a perovskite solar cell.