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Abstract:

The severely insufficient operational lifetime of perovskite light-emitting diodes (LEDs) is incompatible with the rapidly increasing external quantum efficiency, even as it approaches the theoretical limit, thereby significantly impeding the commercialization of perovskite LEDs. In addition, Joule heating induces ion migration and surface defects, degrades the photoluminescence quantum yield and other optoelectronic properties of perovskite films, and induces the crystallization of charge transport layers with low glass transition temperatures, resulting in LED degradation under continuous operation. Here, a novel thermally crosslinked hole transport material, poly(FCA₆₀ -co-BFCA₂₀ -co-VFCA₂₀ ) (poly-FBV), with temperature-dependent hole mobility is designed, which is advantageous for balancing the charge injection of the LEDs and limiting the generation of Joule heating. The optimised CsPbI₃ perovskite nanocrystal LEDs with poly-FBV realise approximately a 2-fold external quantum efficiency increase over the LED with commercial hole transport layer poly(4-butyl-phenyl-diphenyl-amine) (poly-TPD), owing to the balanced carrier injection and suppressed exciton quenching. Moreover, because of the Joule heating control provided by the novel crosslinked hole transport material, the LED utilising crosslinked poly-FBV has a 150-fold longer operating lifetime (490 min) than that utilizing poly-TPD (3.3 min). The study opens a new avenue for the use of PNC LEDs in commercial semiconductor optoelectronic devices.

Abstract:

The power conversion efficiency of tin-based halide perovskite solar cells is limited by large photovoltage losses arising from the significant energy-level offset between the perovskite and the conventional electron transport material, fullerene C₆₀. The fullerene derivative indene-C₆₀ bisadduct (ICBA) is a promising alternative to mitigate this drawback, owing to its superior energy level matching with most tin-based perovskites. However, the less finely controlled energy disorder of the ICBA films leads to the extension of its band tails that limits the photovoltage of the resultant devices and reduces the power conversion efficiency. Herein, we fabricate ICBA films with improved morphology and electrical properties by optimizing the choice of solvent and the annealing temperature. Energy disorder in the ICBA films is substantially reduced, as evidenced by the 22 meV smaller width of the electronic density of states. The resulting solar cells show open-circuit voltages of up to 1.01 V, one of the highest values reported so far for tin-based devices. Combined with surface passivation, this strategy enabled solar cells with efficiencies of up to 11.57%. Our work highlights the importance of controlling the properties of the electron transport material toward the development of efficient lead-free perovskite solar cells and demonstrates the potential of solvent engineering for efficient device processing.

Abstract:

This paper discusses sustainable renewable energy policies. The method used in this paper is a descriptive method that collects data from various sources literature studies and previous research. The results of the literature review show that the development of renewable energy in the European Union has three clusters dividing the share of renewable energy and the degree of dependency on energy imports based on the country. In Pakistan, the government has been designing a renewable energy policy since 2006 to supply sustainable energy to all consumers. In Nigeria, the electricity crisis and the need to reduce greenhouse gases spurred the development of renewable energy. Denmark has moved to wind power sources by increasing the share of renewable energy in the domestic electricity supply. The government encourages local ownership in the renewable energy sector, and many neighborhoods are connected to district heating systems that use renewable energy such as biomass. Increased investment in renewable energy technology will aid in addressing global energy concerns and hastening the transition to a low-carbon economy.Tulisan ini membahas tentang kebijakan energi terbarukan berkelanjutan. Metode yang digunakan dalam tulisan ini adalah metode deskriptif yang mengumpulkan data dari berbagai sumber dan studi literatur serta penelitian terdahulu. Hasil dari tinjauan literatur menunjukkan bahwa perkembangan energi terbarukan di Uni Eropa memiliki tiga kluster yang membagi negara-negara berdasarkan pangsa energi terbarukan dan tingkat ketergantungan impor energi. Di Pakistan, pemerintah telah merancang kebijakan energi terbarukan sejak tahun 2006 untuk memasok energi berkelanjutan kepada semua konsumen. Di Nigeria, krisis listrik dan kebutuhan untuk mengurangi gas rumah kaca memacu pengembangan energi terbarukan. Meskipun Nigeria memiliki potensi energi terbarukan yang besar, perkembangannya masih lambat. Diperlukan upaya lebih lanjut untuk meningkatkan pemanfaatan energi terbarukan melalui perjanjian kemitraan swasta, investasi dalam penelitian dan pengembangan, dan kebijakan berorientasi pasar.  Denmark telah melakukan peralihan ke sumber energi terbarukan dengan meningkatkan pangsa energi terbarukan dalam pasokan listrik domestik. Tenaga angin menjadi salah satu komponen utama energi terbarukan di Denmark. Pemerintah mendukung kepemilikan lokal dalam sektor energi terbarukan, dan sejumlah besar rumah tangga terhubung ke pemanas distrik yang menggunakan energi terbarukan seperti biomassa. Investasi yang lebih besar dalam teknologi energi terbarukan akan membantu mengatasi tantangan energi global dan mempercepat transisi ke ekonomi rendah karbon yang berkelanjutan