Al-Zalzalah/The Earthquak
I/We begin by the Blessed Name of Allah
The Immensely Merciful to all, The Infinitely Compassionate to everyone.
99:01
a. When the earth will be shaken violently in its mighty quaking to its very core,
99:02
a. and when the earth will throw out its burdens of the dead from their graves,
99:03
a. and when the human being will be crying out in panic:
b. ‘What is happening to it?’
99:04
a. At that Time it - the earth - will narrate its news,
99:05
a. for your Rabb - The Lord would have commanded it to do so.
99:06
a. That Time the people will proceed in separate groups,
b. so that they may be shown the results of their worldly deeds and dealings.
99:07
a. So whoever would have done good, even to the weight of a particle, will see it, and be rewarded for it.
99:08
a. And whoever would have done evil, even to the weight of a particle, will see it, and be rewarded for it.
Islamic cardinal precepts include seeking benefaction and patronage of other Muslims. Generally, Islamic history is replete with such munificent and generous personages as were ever geared up to serving humanity, yet the golden era of Islamic history excelled in profusion of such noble persons. When we review the aspect of serving mankind in the life history of the reverend Sahaba (the holy prophet’s disciples), we come to know that they had highly remarkable passions for helping, beneficing, supporting and sustaining their relatives, friends as well as the common run. The level of their charity was so great that they felt felicity and prostrated to Allah in gratitude even after giving away their all possessions and belongings for Allah’s sake only. In fact, the motivation behind this generosity was the attainment of pleasing Allah and the obedience and submission to the holy prophet. They had no iota of worldly voracity or avarice. Therefore, they were ever elated over giving away their assets.
Silicon is still the dominant photovoltaic technology with over 90% share in the solar cell market. Prices of silicon solar cells have drastically reduced in the past few years which has led to its widespread adoption, but manufacturing of these cells requires huge capital and running cost and the processes involved are extremely time and energy intensive.For solar cells to become ubiquitous their cost needs to be significantly lowered. This can be done through new approaches which involve cheap materials and easy processing. Perovskite and dye sensitized solar cells have emerged as cost effective alternatives to the silicon solar cells due to their simple and easy processing and inexpensive constituents. Although perovskite solar cells have demonstrated a lab scale power conversion efficiency of over 22% but their ambient air synthesis and long-term stability against moisture and water remains a challenge to their commercial exploitation. Different approaches including a water resistive top coating on perovskite cells, substituting iodide with chloride ion and methyl group with formamidinium cation, constructing two-dimensional layered morphologies and morphology engineering using co-solvents and additives have been explored to address these issues. Among these approaches, additive engineering due to its ease of incorporation, simplicity and unprecedented control over the nature and architecture of substituents offers huge advantage over all the rest.This thesis presents results of the ambient-air synthesis and stability studies of perovskite solar cells prepared using additives with hydrophobic and hydrophilic substituents. To realize perovskite solar cells two-step approach was employed. Ethanolamine (EA), dibutylamine (DBA) and dibutylethanol amine (DBEA) were used as complexing agents to modify the nucleation and crystallization behavior of lead iodide during film formation. All three additives significantly enhanced solubility of lead iodide in dimethylformamide (DMF). Perovskite films prepared using EA, DBA and DBEA showed much improved surface coverages, larger and uniform grain sizes and much enhanced uniformities compared to pristine film, which exhibited gross phase separation. Power conversion efficiencies (PCE) of over 3%, 5% and 10.8% were obtained for EA, DBA and DBEA incorporated perovskites whereas pristine devices exhibited PEC values of under 1%.Photoluminescence (PL) spectroscopy confirms IV results that charge recombination is drastically reduced by the addition of these additives and the lowest recombination was observed for DBEA. Similar trend was observed for air-stability tests where DBEAincorporated devices showed highest stability (over 750 h) followed by DBA (over 500 h) and then EA (less than 200 h). Under same environmental conditions, pristine devices were found to be completely degraded within 150 h. Second part of this thesis reports on the efficiency enhancement of dye sensitized solar cells by directly depositing gold (Au) nanoparticles on the mesoporous titania scaffold before dye xii sensitization. Cells based on these photoanodes showed 9.48% efficiency compared to 6.1% for the reference cell, exhibiting an overall enhancement of 55% using only 0.11 wt% of Au, which is the lowest reported Au concentration for DSSCs in the literature to-date. We also report on the use of biomass-derived nitrogen-doped carbon aerogel as an effective alternative to conventional platinum based counter electrodes for dye sensitized solar cells. The nitrogen-doped carbon aerogel electrode, deposited from oleylamine mixture, was annealed at different temperatures and its impact on photovoltaic performance of these cells is investigated. I-V measurements confirm that the annealing temperature substantially enhances photovoltaic parameters of these devices. The power conversion efficiency of the solar cells from optimized nitrogen-doped carbon aerogel exhibited comparable efficiency to that of a cell fabricated using platinum-based counter electrode.