Temperature‐Dependent Lifetime and Photoluminescence Measurements

Temperature-dependent measurements are extensively employed in assessing photovoltaic materials and devices. An obvious reason is that solar cells often operate at temperatures significantly divergent from the 25 °C designated as 'standard test conditions'. Consequently, temperature-dependent measurements prove advantageous in evaluating the performance of solar cells under actual operational circumstances. Furthermore, incorporating temperature as a variable in the measurements often allows the precise extraction of material properties. In this chapter, two extensively utilized and powerful temperature-dependent characterization techniques are reviewed. The first method is temperature- and injection-dependent lifetime spectroscopy, which is potent for investigating recombination-active defects in semiconductor materials. Minimizing defect-induced recombination is an enduring focus for solar cells. The challenge lies in the fact that certain deleterious defects can significantly limit the performance of solar cells, even when present at a very dilute concentration below the detection thresholds of most conventional characterization techniques. Temperature- and injection-dependent lifetime spectroscopy emerges as a valuable tool in such instances, given its sensitivity to recombination activity rather than the absolute concentration of defects. This chapter meticulously examines the theory and analytical methods of this technique. The second method under review is temperature-dependent photoluminescence imaging. In the realm of solar cells, where the areas continue to expand, the significance of photoluminescence imaging, with its rapid and spatially-resolved capabilities, grows exponentially. This chapter explores the applications of temperature-dependent photoluminescence imaging and underscores the additional insights that can be gleaned by introducing temperature variations.