Jurnal Creative Research in Engineering – Vol. 2, No. 2, 2022, pp. 63-71 Creative Research in Engineering 63 Research Article Kajian Teoritik Efek Pelarut pada Coumarin untuk Aplikasi Dye Sel Surya Siti Zulaehah 1* , Eqwar Saputra 1 , Trio Nur Wibowo 1 , Riri Jonuarti 2 , Nadhratun Naiim Mobarak 3 , Wahyu Tri Cahyanto 4 1 Program Studi Teknik Mesin, Fakultas Teknik dan Sains, Universitas Muhammadiyah Purwokerto, Indonesia 2 Program Studi Fisika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Negeri Padang, Indonesia. 3 Department of Chemical science, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Malaysia 4 Program Studi Fisika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Jenderal Soedirman, Indonesia. Corresponding author: s.zulaehah@ump.ac.id ARTICLE INFO Article History: Received : 26 June 2022 Revised : 27 July 2022 Accepted : 3 August 2022 Available online : 9 August 2022 ABSTRACT Dye-sensitized solar cell (DSSC) is one of the important devices in which the most common technology used for transferring solar energy into electricity, yet the efficiency is still relatively low. Basic coumarin dye has a high potential for operating in DSSC as they have environmentally friendly and easy to fabricate. To understand molecular structure behaviour as an elementary step, we study the geometrical structure, electronic and photo-physical properties of basic coumarin dye in solvent using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) computational method. The results show that the effect of solvent in the basic coumarin dye will stabilise the coumarin structure. The presence of solvent also increases the gap of the highest occupied molecular orbital (HOMO) - the lowest unoccupied molecular orbital (LUMO), oscillator strength, and have higher light-harvesting efficiency (LHE), as well as a red shift in the UV absorption spectra. These results suggest that the solvent has better properties for application in DSSC for basic coumarin. ABSTRAK Dye-sensitized solar cell (DSSC) merupakan salah satu piranti penting di mana teknologi paling umum digunakan untuk mentransfer energi matahari menjadi listrik, namun efisiensinya masih relatif rendah. Pewarna coumarin dasar memiliki potensi yang cukup tinggi untuk digunakan di DSSC dengan sifat yang ramah lingkungan dan mudah produksi. Adapun tujuan Keywords: Basic coumarin, TD-DFT, DSSC, Solvent Creative Research in Engineering |ISSN (Print): 2774-8278|ISSN (Online): 2774-8006