Polarized red, green, and blue light emitting diodes fabricated with identical device configuration using rubbed PEDOT:PSS as alignment layer*

Abstract

Polarized red, green, and blue light emitting diodes (LEDs) are successfully fabricated using polyfluorene and its derivatives, namely, poly (9,9-dioctylfluorene) (PFO), poly (9,9-dioctylfluorene-co-benzothiadiazole) (F8BT), and poly (triphenylamine-co-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole-co-benzo[c]thiadiazole-co-9,9-dioctyl-9H-fluorene) (Red F). Rubbed hole transport layer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) is employed in the devices as the alignment layer to achieve fully monodomain alignment in all polymer layers. Red F is blended with F8BT to realize the polarized electroluminescence of red light (dichroic ratio ∼3.3), despite having no liquid crystallinity itself. Comparing PFO/F8BT blend to F8BT, higher efficiency of polarized emission is found due to the energy transfer. All the polarized LEDs exhibit pronounced dichroism and efficient polarized emission compared to the non-alignment regular devices.

Temperature-dependent barrier height inhomogeneities in PTB7:PC71BM-based organic solar cells

“…Nevertheless, the market needs devices with a low industrial price and permitting the design of devices on big areas and bendable supports. [1] Solar cells based on organic semiconductors validate these requirements. [2,3] However, intense researches are still performed to investigate the practicability of putting it on the market in terms of yield and reliability.…”

Toward Electrically Pumped Organic Lasers: A Review and Outlook on Material Developments and Resonator Architectures

“…For comparison, in an organic sandwich-type structure, the estimation of minimum current density to reach the lasing threshold is %100 A cm À2 . [12b,37] Typical OLED devices are usually driven under much smaller current densities in the range of 0.01 Acm À2 , [38] yet current densities of the order kA cm À2 or 100 kA cm À2 can be reached in OLEDs [39a] and in light-emitting field-effect transistors (LEFETs), respectively. [39b,c] Considering the extra losses mentioned above, the current density needed to achieve net gain can easily exceed this value.…”