Featured Research

from universities, journals, and other organizations

Insights into a new class of semiconducting materials

Date:
August 12, 2014
Source:
University of Notre Dame
Summary:
A new paper describes investigations of the fundamental optical properties of a new class of semiconducting materials known as organic-inorganic 'hybrid' perovskites.

A new paper by University of Notre Dame researchers describes their investigations of the fundamental optical properties of a new class of semiconducting materials known as organic-inorganic "hybrid" perovskites.

Related Articles


The research was conducted at the Notre Dame Radiation Laboratory by Joseph Manser, a doctoral student in chemical and biomolecular engineering, under the direction of Prashant Kamat, Rev. John A. Zahm Professor of Science. The findings appear in a paper in the August 10 edition of the journal Nature Photonics.

The term "perovskites" refers to the structural order these materials adopt upon drying and assembling in the solid state.

"Hybrid perovskites have recently demonstrated exceptional performance in solid-state thin film solar cells, with light-to-electricity conversion efficiencies approaching nearly 20 percent," Manser said. "Though currently only at the laboratory scale, this efficiency rivals that of commercial solar cells based on polycrystalline silicon. More importantly, these materials are extremely easy and cheap to process, with much of the device fabrication carried out using coating and or printing techniques that are amenable to mass production. This is in stark contrast to most commercial photovoltaic technologies that require extremely high purity materials, especially for silicon solar cells, and energy-intensive, high-temperature processing."

Manser points out that although the performance of perovskite solar cells has risen dramatically in only a few short years, the scientific community does not yet fully know how these unique materials interact with light on a fundamental level.

Manser and Kamat used a powerful technique known as "transient absorption pump-probe spectroscopy" to examine the events that occur trillions of a second after light absorption in the hybrid methylammonium lead iodide, a relevant material for solar applications. They analyzed both the relaxation pathway and spectral broadening in photoexcited hybrid methylammonium lead iodide and found that the excited state is primarily composed of separate and distinct electrons and holes known as "free carriers."

"The fact that these separated species are present intrinsically in photoexcited hybrid methylammonium lead iodide provides a vital insight into the basic operation of perovskite solar cells," Manser said. "Since the electron and hole are equal and opposite in charge, they often exist in a bound or unseparated form known as an 'exciton.' Most next-generation' photovoltaics based on low-temperature, solution-processable materials are unable to perform the function of separating these bound species without intimate contact with another material that can extract one of the charges. "

This separation process siphons energy within the light absorbing layer and restricts the device architecture to one of highly interfacial surface area. As a result, the overall effectiveness of the solar cell is reduced.

"However, from our study, we now know that the photoexcited charges in hybrid perovskites exist in an inherently unbound state, thereby eliminating the additional energy loss associated with interfacial change separation," Manser said. "These results indicate that hybrid perovskites represent a 'best of both worlds' scenario, and have the potential to mitigate the compromise between low-cost and high-performance in light-harvesting devices."

Although the research was on the fundamental optical and electronic properties of hybrid perovskites, it does have direct implications for device applications. Understanding how these materials behave under irradiation is necessary if they are to be fully optimized in light-harvesting assemblies.

Manser and Kamat's research was supported by the Department of Energy's Office of Basic Energy Science.


Story Source:

The above story is based on materials provided by University of Notre Dame. The original article was written by William G. Gilroy. Note: Materials may be edited for content and length.


Journal Reference:

  1. Joseph S. Manser, Prashant V. Kamat. Band filling with free charge carriers in organometal halide perovskites. Nature Photonics, 2014; DOI: 10.1038/nphoton.2014.171

Cite This Page:

University of Notre Dame. "Insights into a new class of semiconducting materials." ScienceDaily. ScienceDaily, 12 August 2014. <www.sciencedaily.com/releases/2014/08/140812163529.htm>.
University of Notre Dame. (2014, August 12). Insights into a new class of semiconducting materials. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2014/08/140812163529.htm
University of Notre Dame. "Insights into a new class of semiconducting materials." ScienceDaily. www.sciencedaily.com/releases/2014/08/140812163529.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com
Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
Raw: Paralyzed Marine Walks With Robotic Braces

Raw: Paralyzed Marine Walks With Robotic Braces

AP (Nov. 21, 2014) Marine Corps officials say a special operations officer left paralyzed by a sniper's bullet in Afghanistan walked using robotic leg braces in a ceremony to award him a Bronze Star. (Nov. 21) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins