Browsing by Autor "Franklin Jaramillo"

Now showing 1 - 9 of 9

Hidden energy levels? Carrier transport ability of CdS/CdS1−xSex quantum dot solar cells impacted by Cd–Cd level formation
(Royal Society of Chemistry, 2018) Andrés F. Gualdrón‐Reyes; Ángel M. Meléndez; Juan Tirado; Mario Alejandro Mejía Escobar; Franklin Jaramillo; Martha E. Niño-Gómez
Hidden Cd–Cd energy levels formed in Cd–chalcogenides impact both light harvesting and electron transport in quantum dot-sensitized solar cells.
High efficiency single-junction semitransparent perovskite solar cells
(Royal Society of Chemistry, 2014) Cristina Roldán‐Carmona; Olga Malinkiewicz; Rafael Betancur; Giulia Longo; Cristina Momblona; Franklin Jaramillo; Luis Camacho; Henk J. Bolink
Semitransparent efficient methylammonium lead iodide perovskite based solar cells.
Improving the reproducibility of hybrid perovskite film deposition by Slot-Die Coating
(2022) Alejandra Florez Velasquez; Daniel Ramirez Zora; Franklin Jaramillo
Low organic content hybrid perovskite (Cs1-xDMAx)Pb(Br1-xIx)3 with increased stability for solar cell fabrication
(National University of Colombia, 2023) Juan J. Patiño; Juan Felipe Montoya; Edwin Alexander Ramírez; Franklin Jaramillo; Daniel Ramírez
Hybrid perovskites with reduced organic content have brought great interest for solar cells applications. Particularly, adding inorganic cations increase material stability, by providing an adequate tolerance factor. However, these cations lead to lower absorption coefficient than using only organic cations, therefore it is necessary to implement strategies for having films with appropriate thickness and good light absorption properties. In this work, several experiments were performed with ((Cs1-xDMAx)Pb(Br1-xIx)3 perovskite films of different thicknesses, resulting in devices with photovoltaic conversion efficiency (PCE) near 80% of the reference MAPbI3 cell, high purity phase, appropriate morphology, and higher stability. The perovskite successfully maintained integrity for 12 days in air with relative humidity between 30 and 40%, indicating the fulfillment of the study's objectives.
Optimization of the Ag/PCBM interface by a rhodamine interlayer to enhance the efficiency and stability of perovskite solar cells
(Royal Society of Chemistry, 2017) John Ciro; Santiago Mesa; José Ignacio Uribe; Mario Alejandro Mejía Escobar; Daniel Ramírez; Juan Felipe Montoya; Rafael Betancur; Hyun-Seok Yoo; Nam‐Gyu Park; Franklin Jaramillo
Effective control of the interface between the metal cathode and the electron transport layer (ETL) is critical for achieving high performance p-i-n planar heterojunction perovskite solar cells (PSCs). Several organic molecules have been explored as interlayers between the silver (Ag) electrode and the ETL for the improvement in the photovoltaic conversion efficiency (PCE) of p-i-n planar PSCs. However, the role of these organic molecules in the charge transfer at the metal/ETL interface and the chemical degradation processes of PSCs has not yet been fully understood. In this work, we systematically explore the effects of the interfacial modification of the Ag/ETL interface on PSCs using rhodamine 101 as a model molecule. By the insertion of rhodamine 101 as an interlayer between Ag and fullerene derivatives (PC60BM and PC70BM) ETLs improve the PCE as well as the stability of p-i-n planar PSCs. Atomic force microscopy (AFM) characterization reveals that rhodamine passivates the defects at the PCBM layer and reduces the band bending at the PCBM surface. In consequence, charge transfer from the PCBM towards the Ag electrode is enhanced leading to an increased fill factor (FF) resulting in a PCE up to 16.6%. Moreover, rhodamine acts as a permeation barrier hindering the penetration of moisture towards the perovskite layer as well as preventing the chemical interaction of perovskite with the Ag electrode. Interestingly, the work function of the metal cathode remains more stable due to the rhodamine incorporation. Consequently, a better alignment between the quasi-Fermi level of PCBM and the Ag work function is achieved minimizing the energy barrier for charge extraction. This work contributes to reveal the relevance of proper interfacial engineering at the metal-cathode/organic-semiconductor interface.
Outdoor performance of perovskite solar minimodules: Ideality factor analysis and encapsulation challenges
(2023) Franklin Jaramillo; Esteban Velilla; Daniel Ramírez; E.R. Ramirez; Julian Sánchez Gil
Photophysics behind highly luminescent two-dimensional hybrid perovskite (CH3(CH2)2NH3)2(CH3NH3)2Pb3Br10 thin films
(Royal Society of Chemistry, 2018) Daniel Ramírez; José Ignacio Uribe; Luca Francaviglia; Pablo Romero‐Gómez; Anna Fontcuberta i Morral; Franklin Jaramillo
Two-dimensional (2D) Ruddlesden–Popper perovskites have emerged as a new class of hybrid materials with high photoluminescence and improved stability compared to their three-dimensional (3D) counterparts.
Some Properties of Natural Fibers (Sisal, Pineapple, and Banana) in Comparison to Man-Made Technical Fibers (Aramide, Glass, Carbon)
(Taylor & Francis, 2015) B. E. B. Uribe; Franklin Jaramillo; Maryory Astrid Gómez Botero
In this paper, we analyze the results of the delignification treatments performed on three natural fibers (sisal, pineapple, and banana) and of the thermal treatments at 400, 600, and 800°C on three industrial fibers (aramid, carbon, and glass). The fibers were analyzed by TGA, SEM, and EDS, as well as tested for tensile strength before and after the delignification and thermal treatments. Contact angle measurements were also carried out on the natural fibers. With the delignification treatments, the removal of Si, K, and Mg on pineapple and banana fibers was achieved. Thermal treatments lowered significantly the tensile strength of industrial fibers, while delignification treatments decreased slightly the mechanical resistance of natural fibers, except in the case of the pineapple fiber.
The role of boron in the carrier transport improvement of CdSe-sensitized B,N,F-TiO2 nanotube solar cells: a synergistic strategy
(Royal Society of Chemistry, 2018) Andrés F. Gualdrón‐Reyes; Ángel M. Meléndez; Mario Alejandro Mejía Escobar; Franklin Jaramillo; Martha E. Niño-Gómez
The presence of boron intensifies the synergistic effect of doping and sensitization to improve charge carrier transport into solar devices.