Abstract:Following the increasing global awareness of the dangers posed by the present state of climate change, many countries such as Uganda have adapted long-term plans for a transition to decarbonised economies. A major strategy for decarbonisation is to replace fossil fuels with renewable energy (RE) sources as the fundamental energy source. Uganda has substantial RE resources for the provision of energy services and production, yet these resources remain untapped. It is therefore crucial that the use of these abundant resources should be heightened. This paper examines and discusses the potential and current RE utilization and development in Uganda from the perspective of sustainable development. The status of the different RE resources and their application/utilization, including details of existing projects in the country, are carefully explored and discussed. The possible drivers for a huge advancement of RE applications and development in Uganda are also discussed before elucidating the major barriers and challenges faced by the energy sector as regards RE. Measures and policies required to facilitate the utilization of RE in Uganda are proposed. These evidence-based policies could guide the delivery of affordable and sustainable energy solutions for all by 2030 in Uganda.

This paper presents the results of a combined experimental and analytical/computational study of the effects of pressure on photoconversion efficiencies of perovskite solar cells (PSCs). First, an analytical model is used to predict the effects of pressure on interfacial contact in the multilayered structures of PSCs. The PSCs are then fabricated before applying a range of pressures to the devices to improve their interfacial surface contacts. The results show that the photoconversion efficiencies of PSCs increase by ~40%, for applied pressures between 0 and ~7 MPa. However, the photoconversion efficiencies decrease with increasing pressure beyond ~7 MPa. The implications of the results are discussed for the fabrication of efficient PSCs.

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Incorporation of cesium (Cs) into the perovskite layer has become a good strategy to boost the stability and power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, a suitable and scalable method of Cs incorporation in a perovskite film that does not cause a significant increase in the optical bandgap is needed. In this paper, we introduce a thin layer of CsBr into a formamidinium (FA)-rich mixed halide perovskite film using the thermal evaporation technique. The effects of the thickness of the CsBr layer on the microstructural, structural, and optoelectronic properties and surface chemical states of the perovskite film are then studied. The results indicate that the CsBr layer thickness is able to tune the microstructural and optoelectronic properties of the perovskite film. Planar PSCs fabricated with different thicknesses of CsBr layers in the perovskite absorber exhibited different photovoltaic performance characteristics. The CsBr-modified PSC device with a 50 nm layer of CsBr in the perovskite layer showed a better PCE of 16.19% ± 0.17%, which was about 15% higher than that of the control device, and was able to retain nearly 70% of its initial PCE value after 120 days of storage in an unencapsulated state.

In this study, we reported a low-temperature, one-step solution process to fabricate perovskite solar cells using dehydrated lead acetate as the lead source. These perovskite films were aged at 200 s before thermal annealing at 90 °C for 5 min. Uniform perovskite films with lesser pinholes were obtained by this technique. The inverted planar (n-i-p) perovskite solar cell device resulted in a power conversion efficiency of 13%. A substantial finding was that the devices demonstrated high reproducibility. We also investigated the effect of annealing temperature on the optical and structural properties of the films and on the photovoltaic performances of the fabricated solar cell devices. For the aforementioned, a low-temperature, onestep solution process, the optimal temperature was achieved at 90 °C.

The design of electron transport layers (ETLs) with good optoelectronic properties is one of the keys to the improvement of the power conversion efficiencies (PCEs) and stability of perovskite solar cells (PSCs). Titanium dioxide (TiO2), one of the most widely used ETL in PSCs, is characterized by low electrical conductivity that increases the series resistance of PSCs, thus limiting their PCEs. In this work, we incorporated tin oxide (SnO2) into titanium dioxide (TiO2) and studied the evolution of its microstructural and optoelectronic properties with SnO2 loading. The thin films were then integrated as ETLs in a regular planar Formamidinium (FA)-rich mixed lead halide PSCs so as to assess the overall effect of SnO2 incorporation on their charge transport and Photovoltaic (PV) characteristics. Analysis of the fabricated PSCs devices revealed that the best performing devices; based on the ETL modified with 0.2 proportion of SnO2; had an average PCE of 17.35 ± 1.39%, which was about 7.16% higher than those with pristine TiO2 as ETL. The improvement in the PCE of the PSC devices with 0.2 SnO2 content in the ETL was attributed to the improved electron extraction and transport ability as revealed by the Time Resolved Photoluminescence (TRPL) and Electrochemical Impedance Spectroscopy (EIS) studies.

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In this paper, we use Polyethylene Oxide (PEO) particles to control the morphology of Formamidinium (FA)-rich perovskite films and achieve large grains with improved optoelectronic properties. Consequently, a planar perovskite solar cell (PSC) is fabricated with additions of 5 wt% of PEO, and the highest PCE of 18.03% was obtained. This solar cell is also shown to retain up to 80% of its initial PCE after about 140 h of storage under the ambient conditions (average relative humidity of 62.5 ± 3.25%) in an unencapsulated state. Furthermore, the steady-state PCE of the PEO-modified PSC device remained stable for long (over 2500 s) under continuous illumination. This addition of PEO particles is shown to enable the tuning of the optoelectronic properties of perovskite films, improvements in the overall photophysical properties of PSCs, and an increase in resistance to the degradation of PSCs.