The investigation of stability of n-CdS/p-Cu₂S solar cells prepared by cold substrate method

Abstract

In this study, two different n-CdS/p-Cu2S solar cells were prepared by evaporating Cu at different substrate temperatures (200 K and 300 K) by vacuum evaporation method on a single crystal CdS semiconductor. Field emission scanning electron microscope images showed that the Cu layer obtained at a temperature of 200 K was composed of nanoparticles in accordance with the soliton growth mechanism. Cu film thickness was determined as 395 ∓ 0.76 nm at 300 K substrate temperature and 187 ∓ 0.45 nm at 200 K substrate temperature. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the solar cells were examined for 12 weeks in dark and light environments. Open-circuit voltage (V oc), short-circuit current (I sc), maximum power (P max), filling factor and efficiency (η) were calculated from I–V measurements. For the prepared solar cells, the highest efficiency value was obtained in the 7th week (η= 0.1360) at 200 K substrate temperature, while it was obtained in the 5th week (η = 0.0384) at 300 K substrate temperature. From C–V measurements, donor density (N d) and barrier potential (V bi) were calculated. The solar cell produced at 200 K substrate temperature has higher donor density (1st week 2.99 × 1016 cm−3) and barrier potential values (12th week 0.411 V). At the end of the 12-week period, the deterioration rate of solar cells created at 200 K and 300 K substrate temperatures was 51% and 94%, respectively.

A theory study based on DFT/TD‐DFT for a series of Ir(III) complexes with the low‐efficiency roll‐off and the high‐inter‐system crossover rate properties

“…Additionally, the data suggest a minimal occurrence of 3 LLCT (ligand-to-ligand charge transfer) between the ligands. For phosphorescent materials, the electron transport orbitals of the 3 LLCT process are lengthier than those of 3 ILCT, which could lead to an extended phosphorescence lifetime, as exemplified by the efficiency roll-off effect [30][31][32]. The complexes devised in this paper are primarily characterized by the 3 ILCT transition, thus leading us to infer their propensity for low-efficiency roll-off characteristics.…”

“…Our calculations reveal the lowest emission wavelengths for each complex. The over-charge transfer pathways typically involve 3 ILCT and 3 MLCT for complexes 2, 3, 4, and 6, with complexes 1 and 5 exhibiting 3 LLCT in addition to the former two. The influence of the tpip on energy transfer and efficiency of Ir(III) complexes has been extensively discussed previously.…”

“…Research into high‐efficiency electroluminescent devices has spurred rapid advancements in materials for organic light‐emitting devices (OLEDs) [1–3]. In contrast to traditional organic small molecules and conjugated polymers, transition metal complexes offer the potential for achieving a maximum internal electroluminescence quantum efficiency of 100%, enabling access to both singlet and triplet excitons simultaneously [4, 5].…”

Effect of substrate type on the physical properties of thermally evaporated CdS thin films for CdTe/CdS solar cells applications

“…CdS thin film is a promising window layer in a heterojunction structure with CdTe and copper indium gallium selenide (CIGS) because of its excellent transport properties [1,8]. TFSCs, such as CdTe and CIGS, are formed with p-n junctions using p-type materials as the absorber layer (CdTe or Cu 2 S) and n-type materials as the window one [9]. Optimizing the physical properties of CdS thin films is crucially essential to improve the performance of optoelectronic devices.…”