Solid‐State Photovoltaic Thin Films using TiO₂, Organic Dyes, and Layer‐by‐Layer Polyelectrolyte Nanocomposites

Abstract

We report photovoltaic devices consisting of patterned TiO2, porphyrin dyes, and layer‐by‐layer (LBL) polyelectrolyte multilayer/oligoethylene glycol dicarboxylic acid (OEGDA) composite films. A composite polyelectrolyte LBL/OEGDA film was fabricated by formation of an alternating multilayer of linear polyethyleneimine (LPEI) and polyacrylic acid (PAA), followed by immersion of the LBL film into an OEGDA aqueous solution. The ionic conductivity attained in this LBL LPEI/PAA and OEGDA composite film was approximately 10–5 S cm–1 at room temperature and humidity. Investigations of dye‐sensitized photovoltaic devices constructed with the LBL (LPEI/PAA)/OEGDA composite films, TiO2, and four types of porphyrin dyes resulted in optimization of the dye molecule and its orientation at the interface with the ionically conductive composite. The photocurrent value of photovoltaic devices constructed with the composite LBL/OEGDA film from illumination of a xenon white light source exhibited a nearly 1.5 times enhancement over the device without OEGDA. This enhancement of the photocurrent was due to the high room‐temperature ionic conductivity of the multilayer composite film. Further marked improvements of the photovoltaic performance were achieved by patterning the TiO2 electrode using polymer stamping as a template for TiO2 deposition. The device with patterned TiO2 electrodes exhibited almost 10 times larger conversion efficiencies than a similar device without patterning.

Form and Function in Multilayer Assembly: New Applications at the Nanoscale

“…The incorporation of low molecular weight diacid ethylene oxide derivatives (OEGDA) in acidic water in the presence of LiI salts were found to result in ionic conductivities of 10 ±5 at room humidities. [61] Further investigations have indicated that when fully formed LPEI/PAA films are introduced to the OEGDA/LiI aqueous solution at low pH, the OEGDA is incorporated in large quantities into the interior of the film. It has recently been determined that the high levels of incorporation are due to a transition from a continuous to a nanoporous film morphology due to spinodal decomposition and phase segregation upon protonation of highly charged acid groups at pH 2±3; these transitions, which will be discussed in a following section, were first discovered and investigated by Rubner and co-workers in PAH/PAA thin films.…”

Challenges and breakthroughs in recent research on self-assembly

“…Recently, research of this method has become application-oriented as can be seen in several reports including surface modification for superhydrophobicity [868,869], sensor preparation [870][871][872][873][874], electrochromic devices [875], photochromic devices [876], thin film transistors [877], fuel cells [878], solid-state photovoltaic devices [879], rectifying junctions [880], and chiral switching [881].…”

“…Hammond and coworkers proposed the use of chemically patterned surfaces produced by stamping techniques as templates for ionic multilayer assembly based on stamping techniques ( figure 103A(a)) [864,865]. The LbL multilayers, as a polyelectrolyte platform, were deposited on a solid support and terminated by using a layer containing an amine group.…”

Влияние Фотоэлектронных Процессов В Полупроводниковой Подложке На Адсорбцию Поликатионных И Полианионных Молекул

“…Благодаря широкому выбору органических материалов с различными свойствами, такие слои оказываются полезными для создания просвет-ляющих покрытий [1], мембран, в качестве функциональных слоев тран-зисторов [2], солнечных элементов [3], запоминающих устройств [4], а также сенсорных структур электролит−диэлектрик−полупроводник [5]. Задача нашего исследования заключается в том, чтобы максимально использовать возможности полупроводникового материала в процессе нанесения на него органических мультислойных покрытий для придания им необходимых свойств и прогнозирования характеристик гибридной структуры в целом.…”