BEGIN:VCALENDAR VERSION:2.0 PRODID:IEEE vTools.Events//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:America/New_York BEGIN:DAYLIGHT DTSTART:20210314T030000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3 TZNAME:EDT END:DAYLIGHT BEGIN:STANDARD DTSTART:20211107T010000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11 TZNAME:EST END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20220419T210545Z UID:9077721A-0609-4A53-A8EE-F7D1045E60A2 DTSTART;TZID=America/New_York:20210414T120000 DTEND;TZID=America/New_York:20210414T131500 DESCRIPTION:Key advantages of organic photovoltaic (OPV) technology is that organic based PV\, versus traditional inorganic semiconductors\, are inhe rently inexpensive\; typically have very high optical absorption coefficie nts (>105 cm-1)\; are compatible with plastic and flexible substrates\; an d can be fabricated using high-throughput low temperature processes for lo w-cost roll-to-roll (R2R) manufacturing. Organic solar cells have improved rapidly over 20 years from very low efficiencies (~3.5%) to moderately hi gh efficiencies of 15-18.2%\, with the overall performance of OPVs poised for commercial opportunities. The bulk heterojunction topology launched th is revolution.\n\nFundamental limitations for bulk heterojunction OPVs tra ditionally have been (i) narrow absorption spectral region\, (ii) difficul ty to dissociate excitons and (iii) fully collect liberated charged carrie rs. The baseline model used poly(3-hexylthiophene-2\,5-diyl) (P3HT) inters persed with phenyl-C61-Butyric-Acid-Methyl Ester (PCBM)\, as a mixture of conjugated polymers with functionalized fullerenes\, and only the P3HT abs orbs sunlight\, while missing the infrared regions of the solar spectrum. PCBM is optically inert\, and does not collect sunlight due to its soccer- ball symmetry of the C60 molecule. With new developed low bandgap absorber s via new conjugated polymer chemistries\, the current platform is expandi ng its narrow collection window to be more spectrally matched to the incid ent solar spectrum. However\, this can create additional issues that will be discussed.\n\nAmong recent advances towards improving the efficiency in organic PV devices\, various interface and surface engineering techniques to the anode have demonstrated improved efficiencies for organic PV devic es by an optimization of the short-circuit current\, the open-circuit volt age and the fill factor. Although direct surface modifications to the anod e have been successfully implemented for organic light emitting diodes (OL ED) to improve their device performance by creating an interface energy st ep between the anode and the hole-transporting layer\, thereby enhancing h ole injection by effectively lowering the hole injection barrier\, this ap proach had not been fully explored for organic PV yet. In this talk\, I wi ll also present efficient PV devices through tailored modifications to ele ctrode surfaces.\n\nIn order to improve the efficiency of polymer PV devic es\, another approach\, addressed here\, will be to yield increased optica l absorption and photocurrent generation in the photoactive layer over a b road range of visible wavelengths by inducing surface plasmons through car eful control of metallic nanoparticle’s properties. In this work\, a uni que colloidal silver nanoparticle solution with the presence of suitable o rganic capping groups that stabilize the nanoparticles and inhibit their p ropensity to agglomerate is applied to organic bulk heterojunction PV devi ces. An improved optical absorption and photocurrent for PV devices was de monstrated due to the increased electric field in the photoactive layer by excited localized surface plasmons of Ag nanospheres.\n\nFor completeness \, time permitting\, testing issues specific to OPV\, their packaging and economics will also be reviewed\n\nVirtual: https://events.vtools.ieee.org /m/266345 LOCATION:Virtual: https://events.vtools.ieee.org/m/266345 ORGANIZER:varonides@scranton.edu SEQUENCE:3 SUMMARY:Challenges for Low-Cost Roll-to-Roll Organic Solar Cells: A Review of their Physics\, Limitations\, and a Comparison with Inorganic PV Techno logies URL;VALUE=URI:https://events.vtools.ieee.org/m/266345 X-ALT-DESC:Description: <br /><p>Key advantages of organic photovoltaic (OP V) technology is that organic based PV\, versus traditional inorganic semi conductors\, are inherently inexpensive\; typically have very high optical absorption coefficients (&gt\;10<sup>5</sup> cm<sup>-1</sup>)\; are compa tible with plastic and flexible substrates\; and can be fabricated using h igh-throughput low temperature processes for low-cost roll-to-roll (R2R) m anufacturing. Organic solar cells have improved rapidly over 20 years from very low efficiencies (~3.5%) to moderately high efficiencies of 15-18.2% \, with the overall performance of OPVs poised for commercial opportunitie s. The bulk heterojunction topology launched this revolution.</p>\n<p>Fund amental limitations for bulk heterojunction OPVs traditionally have been ( i) narrow absorption spectral region\, (ii) difficulty to dissociate excit ons and (iii) fully collect liberated charged carriers. The baseline model used poly(3-hexylthiophene-2\,5-diyl) (P3HT) interspersed with phenyl-C61 -Butyric-Acid-Methyl Ester (PCBM)\, as a mixture of conjugated polymers wi th functionalized fullerenes\, and only the P3HT absorbs sunlight\, while missing the infrared regions of the solar spectrum. PCBM is optically iner t\, and does not collect sunlight due to its soccer-ball symmetry of the C <sub>60</sub> molecule. With new developed low bandgap absorbers via new c onjugated polymer chemistries\, the current platform is expanding its narr ow collection window to be more spectrally matched to the incident solar s pectrum. However\, this can create additional issues that will be discusse d.</p>\n<p>Among recent advances towards improving the efficiency in organ ic PV devices\, various interface and surface engineering techniques to th e anode have demonstrated improved efficiencies for organic PV devices by an optimization of the short-circuit current\, the open-circuit voltage an d the fill factor. Although direct surface modifications to the anode have been successfully implemented for organic light emitting diodes (OLED) to improve their device performance by creating an interface energy step bet ween the anode and the hole-transporting layer\, thereby enhancing hole in jection by effectively lowering the hole injection barrier\, this approach had not been fully explored for organic PV yet. In this talk\, I will als o present efficient PV devices through tailored modifications to electrode surfaces.</p>\n<p>In order to improve the efficiency of polymer PV device s\, another approach\, addressed here\, will be to yield increased optical absorption and photocurrent generation in the photoactive layer over a br oad range of visible wavelengths by inducing surface plasmons through care ful control of metallic nanoparticle&rsquo\;s properties. In this work\, a unique colloidal silver nanoparticle solution with the presence of suitab le organic capping groups that stabilize the nanoparticles and inhibit the ir propensity to agglomerate is applied to organic bulk heterojunction PV devices. An improved optical absorption and photocurrent for PV devices wa s demonstrated due to the increased electric field in the photoactive laye r by excited localized surface plasmons of Ag nanospheres.</p>\n<p>For com pleteness\, time permitting\, testing issues specific to OPV\, their packa ging and economics will also be reviewed</p> END:VEVENT END:VCALENDAR