• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.69.1-69.1
• /
• 2010

We have fabricated organic photovoltaic cells (OPVs) with highly conductive poly 3,4-ethylenedioxythiophene : poly styrenesulfonate (PEDOT:PSS) layer as an anode without using transparent conducting oxide (TCO), which has been modified by adding some organic solvents like sorbitol (So), dimethyl sulfoxide (DMSO), N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), and ethylene glycol (EG). The conductivity of PEDOT:PSS film modified with each additive was enhanced by three orders of magnitude. According to atomic force microscopy (AFM) study, conductivity enhancement might be related to better connections between the conducting PEDOT chains. TCO-free solar cells with modified PEDOT:PSS layer and the active layer composed of poly(3-hexylthiophene) (P3HT) and phenyl [6,6] C61 butyric acid methyl ester (PCBM) exhibited a comparable device performance to indium tin oxide (ITO) based organic solar cells. The power conversion efficiency (PCE) of the organic solar cells incorporating DMSO, So + DMSO and EG modified PEDOT:PSS layer reached 3.51, 3.64 and 3.77%, respectively, under illumination of AM 1.5 (100mW/$cm^2$).

• Applied Chemistry for Engineering
• /
• v.27 no.5
• /
• pp.512-515
• /
• 2016

A new viologen derivative namely 1,1'-bis(3,4-dihydroxybutyl)-[4,4'-bipyridine]-1,1'-diium bromide (V-Pr-2OH) was synthesized and applied as a cathode buffer layer to inverted polymer solar cells (PSCs) based on the blend of PTB7 : $PC_{71}BM$. PSCs with the structure of ITO/V-Pr-2OH/PTB7 : $PC_{71}BM/MoO_3/Ag$ as the cathode buffer layer showed the power conversion efficiency (PCE) up to 7.28%, which is comparable to that of the PSCs with the structure of ITO/ZnO/PTB7 : $PC_{71}BM/MoO_3/Ag$ (7.44%) in the absence of V-Pr-2OH. This study demonstrates that a highly efficient PSCs without any high temperature heat treatment can be obtained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.12
• /
• pp.753-764
• /
• 2015

Among several types of energy saving smart window technologies, the leader, the dynamic EC (electrochromic) window one needs integrated PV (photovoltaics), to minimize expensive electrical wiring as well as to obviate the need for external energy. Self-powered smart windows were reviewed according to PV types used. DSSCs (dye sensitized solar cells) were found to be compatible with EC cells, to have several categories of next generation smart windows such as PECCs (photoelectrochromic cells), PVCCs (photovoltachromic cells), EC polymer PECCs. In addition silicon solar cells and third generation solar cells were investigated. They are summarized in a table showing their advantages and disadvantages respectively for a fast comparison. The strategy to expedite the commercialization of these next generation smart windows includes developing retrofit smart window coverings for use on flexible polymer substrates adhered to the inside surface of a window and easily replaced after use for upto 10 years.

• Journal of Electrochemical Science and Technology
• /
• v.4 no.4
• /
• pp.125-139
• /
• 2013

The electrical conductive polymers (ECPs) reported at my research group are introduced in this review, which works are started from the late Professor Su-Moon Park's pioneering research for polyaniline at the University of New Mexico. The electrochemical and spectroelectrochemical properties and their applications to sensor and energy conversion systems are briefly described. At first, the growth and degradation mechanism of polyaniline describes and we extend to polypyrrole, polyazulene, polydiaminonaphthalenes, and polyterthiophene derivatives. In addition, the preparation of monomer precursors having functional groups is briefly described that can give us many exceptional applications for several chemical reactions. We describe the application of these ECPs for the fabrication of chemical sensors, biosensors, biofuel cells, and solar cells.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2008.05a
• /
• pp.15.1-15.1
• /
• 2008

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.398-401
• /
• 2008

Inkjet printing is commonly used in the controlled deposition of solutions of functional materials in specific locations on a substrate, and it can provide easy and fast deposition of polymer films over a large area. which could become a way to manufacturer low cost solar cells. In the present study, inkjet printing technology is adopted to deposit functional layers of PEDOT/PSS solutions and P3HT/PCBM blends for organic solar cell. The results show that merging of separately deposited ink droplets into a continuous, pinhole-free organic thin film could be achieved by a balance between ink property and substrate treatment. As a result, a power conversion efficiency of 2.0% has been accomplished a solar cells applying inkjet technology.

• Polymer Science and Technology
• /
• v.26 no.3
• /
• pp.226-231
• /
• 2015

• Bulletin of the Korean Chemical Society
• /
• v.35 no.5
• /
• pp.1485-1490
• /
• 2014

We have designed and developed a new ladder type tetrafused ${\pi}$-conjugated building block such as dihydroindolo[3,2-b]indole (DINI) and investigated its role as an electron rich unit. The photovoltaic properties of a new semiconducting ${\pi}$-conjugated polymer, poly[[5,10-bisoctyl-5,10-dihydroindolo[3,2-b]indole-[5,6- bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole]], represented by PDINI-OBTC8 are described. The new polymer PDINI-OBTC8 was synthesized in donor-acceptor (D-A) fashion, where fused ${\pi}$-conjugated tetracyclic DINI, and 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl) benzo[c][1,2,5]thiadiazole (OBTC8) were employed as electron rich (donor) and electron deficient (acceptor) moieties, respectively. The conventional bulk heterojunction (BHJ) device structure ITO/PEDOT:PSS/PDINI-OBTC8:PCB71M/LiF/Al was utilized to fabricate polymer solar cells (PSCs), which comprises the blend of PDINI-OBTC8 and [6,6]-phenyl-$C_{71}$-butyric acid methyl ester ($PC_{71}BM$) in BHJ network. A BHJ PSC that contain PDINI-OBTC8 delivered power conversion efficiency (PCE) value of 1.68% with 1 vol% of 1,8-diidooctane (DIO) under the illumination of A.M 1.5G 100 $mW/cm^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.3
• /
• pp.252-256
• /
• 2013

We introduced sensitizing dyes into the bulk-heterojunction (BHJ) photovoltaic (PV) layer of polymer solar cells (PSCs). The sensitizing dyes doped were Bis(tetra butyl ammonium) cis-dithio cyanato bis(2,2'-bipyridine-4-carboxylicacid-4'-carboxylate) ruthenium (II) (N719 dye) and the BHJ PV layer used was made of poly (3-hexylthiophene) (P3HT) and phenyl $C_{61}$-butyric acid methyl ester (PCBM). It was found that the N719 dyes increase the photovoltaic performance, i.e., increasing open-circuit voltage and short-circuit current density with improved fill factor. For the P3HT:PCBM PV cells doped with the N719 dyes (0.24 wt%), an increase in power conversion efficiency of 4.0% was achieved, compared to that of the control cells (3.6%) without the N719 dyes.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.432-433
• /
• 2012

Polymer solar cells are fabricated using electrospray (e-spray) deposition process. It shows comparable performance with reference devices, and has different characteristics according to the thickness of the active layer: In the case of the devices with higher fill factor, it shows relatively lower current density, and vice versa. These films are characterized by atomic force microscopy measurement. The results indicate that the comparable power conversion efficiency made by e-spray results from the 'solvent annealing effect' by process conditions and the different thin film property is caused by the degree of self-organization of the polymer.